[Federal Register Volume 61, Number 15 (Tuesday, January 23, 1996)]
[Proposed Rules]
[Pages 1730-1739]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-877]



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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 136

[FRL-5401-7]


Guidelines Establishing Test Procedures for the Analysis of Oil 
and Grease and Total Petroleum Hydrocarbons

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: This proposed regulation would amend the Guidelines 
Establishing Test Procedures for the Analysis of Pollutants under 
section 304(h) of the Clean Water Act to replace existing gravimetric 
test procedures for the conventional pollutant ``oil and grease'' (40 
CFR 401.16) with EPA Method 1664 as part of EPA's effort to reduce 
dependency on the use of chlorofluorocarbons (CFCs). Method 1664 uses 
normal hexane (n-hexane) as the extraction solvent in place of 1,1,2-
trichloro-1,2,2-trifluoroethane (CFC-113; Freon-113). CFC-113 is used 
in currently approved 40 CFR Part 136 methods for the determination of 
oil and grease. These methods are EPA Method 413.1 in Methods for 
Chemical Analysis of Water and Wastes (EPA-600/4-79-020) and Method 
5520B in Standard Methods for the Examination of Water and Wastewater, 
18th edition. This proposal would withdraw approval of Methods 413.1 
and 5520B to preclude the unacceptable inconsistency between results 
produced by such methods and proposed Method 1664. In an effort to 
provide for the use and depletion of existing laboratory stocks of 
Freon-113, EPA plans to implement the required use of Method 1664 no 
sooner than six months after the final rule is published in the Federal 
Register. Method 1664 is also being proposed for the determination of 
total petroleum hydrocarbons.

 
[[Page 1731]]

DATES: Comments on this proposal must be submitted on or before March 
25, 1996.

ADDRESSES: Send written comments on the proposed rule to ``Method 
1664'' Comment Clerk; Water Docket MC-4101; Environmental Protection 
Agency; 401 M Street, SW.; Washington, DC 20460. Commenters are 
requested to submit any references cited in their comments. Commenters 
are also requested to submit an original and 3 copies of their written 
comments and enclosures. Commenters who want receipt of their comments 
acknowledged should include a self addressed, stamped envelope. All 
comments must be postmarked or delivered by hand by March 25, 1996. No 
facsimiles (faxes) will be accepted.
    Data available: A copy of the comments and supporting documents 
cited in this proposal are available for review at EPA's Water Docket; 
401 M Street, S.W., Washington, DC 20460. For access to the Docket 
materials, call (202) 260-3027 between 9 a.m. and 3:30 p.m. for an 
appointment.
    Electronic versions of Method 1664 will be available via the 
Internet. EPA operates a ``public access server,'' also known as 
``Earth 1,'' through which EPA will include all of the ways that copies 
of the test method manual are available. The Office of Water will put 
the directions about electronic retrieval of the test method manual on 
EPA's Internet ``homepage.'' By doing so, persons interested in 
electronic copies of the method may obtain copies by either (1) 
retrieving the documents from EPA's file transfer protocol (FTP) site 
on the Internet at ftp.epa.gov or gopher.epa.gov (2) retrieving the 
documents by dial-in access at 919-558-0335.

FOR FURTHER INFORMATION CONTACT: Mr. Ben Honaker, Engineering and 
Analysis Division (4303), USEPA Office of Science and Technology, 401 M 
Street, S.W., Washington, DC, 20460, or call (202) 260-2272.

SUPPLEMENTARY INFORMATION:

I. Authority

A. Clean Water Act

    Today's proposal is pursuant to the authority of sections 301, 
304(h), and 501(a) of the Clean Water Act (CWA), 33 U.S.C. 1314(h), 
1361(a) (the ``Act''). Section 301 of the Act prohibits the discharge 
of any pollutant into navigable waters unless the discharge complies 
with an NPDES permit, issued under section 402 of the Act. Section 
304(h) of the Act requires the Administrator of the EPA to ``promulgate 
guidelines establishing test procedures for the analysis of pollutants 
that shall include the factors which must be provided in any 
certification pursuant to section 401 of this Act or permit 
applications pursuant to section 402 of this Act.'' Section 501(a) of 
the Act authorizes the Administrator to ``prescribe such regulations as 
are necessary to carry out his function under this Act.''
    The Administrator also has made these test methods applicable to 
monitoring and reporting of NPDES permits (40 CFR part 122, 
Secs. 122.21, 122.41, 122.44, and 123.25), and implementation of the 
pretreatment standards issued under section 307 of the Act (40 CFR part 
403, Secs. 403.10 and 402.12).

B. Clean Air Act Amendments of 1990

    Today's proposal is also consistent with sections 604, 606 and 608 
of the 1990 Clean Air Act Amendments (CAAA) to phase out production of 
Class I CFCs and reduce use and emissions of Class I CFCs to the lowest 
achievable level, and with section 613 of the CAAA to reduce the 
Federal procurement of products and services that employ Class I CFCs.

II. Background and History

A. Oil and Grease and Petroleum Hydrocarbons Testing

    The background and history of the applicability of EPA's 
Stratospheric Ozone Protection Program to analytical methods requiring 
the use of CFCs in EPA regulatory programs was given in an earlier 
proposal of an alternate test procedure for the determination of oil 
and grease (56 FR 30519-30520, July 3, 1991).
    As stated in the earlier proposal, preliminary efforts to find a 
suitable replacement solvent for Freon-113 in the determination of oil 
and grease were conducted by the Office of Research and Development's 
Environmental Monitoring Systems Laboratory in Cincinnati, Ohio (EMSL-
Ci). Results of that study, presented in the document titled A Study to 
Select a Suitable Replacement Solvent for Freon-113 in the Gravimetric 
Determination of Oil and Grease by F.K. Kawahara, October 2, 1991, 
suggested the use of an 80/20 mixture of n-hexane and methyl tertiary 
butyl ether (MTBE) in place of Freon-113 for oil and grease 
determination. This led to the proposal (56 FR 30519-30524, July 3, 
1991) to replace Freon-113 with the n-hexane:MTBE mixture in CWA and 
RCRA analytical methods for determination of oil and grease. Based on 
comments received concerning this proposal, the EMSL-Ci study results, 
and the need to further investigate alternative solvents, the Office of 
Water and the Office of Solid Waste initiated a multi-phase Freon 
Replacement Study.
1. Phase I of the Freon Replacement Study
    Phase I of the Freon Replacement Study evaluated alternative 
solvents and extraction systems for equivalency to the results produced 
by Freon-113 across a range of real world effluent and solid waste 
samples from a variety of industrial categories. More specifically, 
Phase I focused on (1) the use of five alternative solvents for 
gravimetric determination of oil and grease in aqueous samples by MCAWW 
Method 413.1 (with modifications) and in solid samples by SW-846 Method 
9071A (with modifications) and (2) the use of alternative techniques 
for oil and grease analysis including sonication extraction, solid 
phase extraction (SPE) using cartridges and disks, and a solvent/non-
dispersive infrared technique. The five alternative solvents studied in 
Phase I were n-hexane, methylene chloride (dichloromethane), 
perchloroethylene (tetrachloroethene), DuPont 123 (2,2-dichloro-1,1,1-
trifluoroethane, a hydrofluorochlorocarbon), and the n-hexane:MTBE 
80:20 mixture.
    Results of the tests of gravimetric procedures in Phase I yielded 
the following conclusions: n-hexane should be retained as a possible 
extraction solvent for further study using gravimetric techniques; 
perchloroethylene should be retained for consideration in the use of 
infra-red techniques; and cyclohexane should be introduced for 
consideration with gravimetric techniques based on its similarity to n-
hexane and because of its lower neurotoxicity when compared to n-
hexane.
    Results of tests of alternative techniques in Phase I indicated 
that only sonication extraction of soil and other solids-containing 
samples produced results equivalent to existing techniques that use 
Freon-113. Specifics of the study design, results, and conclusions can 
be found in the Preliminary Report of EPA Efforts to Replace Freon for 
the Determination of Oil and Grease, September 1993, that is included 
in the docket.
    Prior to the commencement of Phase II of the study, two public 
workshops were held, one on May 4, 1993, in Norfolk, VA and the other 
on June 30, 1993, in Boston, MA. The objectives of these workshops were 
to inform interested parties of the results from Phase I and related 
studies, and to 

[[Page 1732]]
provide a forum for the discussion of results, issues, and possible 
solutions to the problem of finding a non-ozone-depleting substance 
that would produce results identical to the results produced by CFC-
113. Detailed records of the information presented, which included data 
from EPA, vendor, and laboratory representatives, as well as the 
proceedings of the question and answer sessions, can be found in the 
reports entitled Oil and Grease Workshop, Norfolk, Virginia, May 4, 
1993 and Oil and Grease Workshop, Boston, Massachusetts, June 30, 1993 
that are also included in the docket for today's proposed rule.
2. Phase II of the Freon Replacement Study
    Based on the conclusions of Phase I of the Freon Replacement Study, 
Phase II was designed to further assess the use of n-hexane as a 
replacement solvent and to evaluate the use of cyclohexane as a 
replacement solvent for oil and grease determination in aqueous samples 
by MCAWW Method 413.1, with modifications to allow for solvent 
densities less than the density of water. In addition, gravimetric 
determination of ``petroleum hydrocarbons'' was evaluated by subjecting 
the extracted oil and grease samples to the silica gel adsorption 
procedure in Standard Methods for the Examination of Water and 
Wastewater (Standard Methods) 5520F (with modifications). This 
procedure removes non-aliphatic hydrocarbons such as detergents, 
surfactants, fatty acids, aromatic hydrocarbons, heterocyclics, and 
some chemical compounds containing nitrogen, phosphorus, and sulfur.
    The final objectives of the Phase II study were to utilize these 
results and comments to choose a replacement solvent and to document 
the analytical protocol implemented to produce the first draft of 
Method 1664 (the ``Method'') for gravimetric determination of oil and 
grease and petroleum hydrocarbons. Following the formal documentation 
of the Method, a further objective was to initiate an interlaboratory 
study using the new method in order to characterize the method and 
generate method specifications in the form of quality control (QC) 
acceptance criteria.
    A total of 34 samples from a combination of in-process and effluent 
waste streams were collected from 25 facilities encompassing 16 
different industrial categories. Samples containing between 40-300 mg/L 
oil and grease, some from petroleum and some from non-petroleum 
sources, were collected. The study focused on this concentration range 
to avoid the problems associated with the comparison and evaluation of 
``non-detect'' results. In order to increase the types of matrices that 
could be analyzed using the Method and better assess the effect of 
different matrices on solvent extraction performance, the Agency 
collected samples from a variety of industrial facilities that were 
different from those collected during Phase I of the study.
    Analysis of each sample was performed in triplicate for each of the 
three extraction solvents. Prior to the analysis of field samples, the 
evaluating laboratory was required to demonstrate its ability to 
generate acceptable accuracy and precision for each of the required 
procedures by performing a series of initial precision and recovery 
(IPR) analyses for determination of oil and grease and petroleum 
hydrocarbons using Freon-113, n-hexane, and cyclohexane as extraction 
solvents. IPR analyses involved extraction, concentration, and analysis 
of a set of four 1-L aliquots of reagent water that had been spiked 
with hexadecane and stearic acid. All IPR analyses included 
modifications necessary to allow for differences in solvent densities 
and other modifications necessary to apply Method 413.1 and Standard 
Method 5520F to the alternative solvents, in order to evaluate any 
effects that might result from the modified procedures.
    An ongoing precision and recovery (OPR) analysis, the equivalent of 
a single IPR sample, was required with each analytical batch for each 
alternative solvent. An analytical batch consisted of a set of samples 
extracted at the same time, to a maximum of ten samples.
    In addition, a reagent water method blank was analyzed with each 
IPR set and with each sample batch for each alternative solvent. These 
reagent water blanks were run through the same extraction and analysis 
procedure through which the samples were run. The analytical protocol 
required that the concentration of oil and grease in method blanks not 
exceed 5 mg/L and, if contamination above this level was detected in 
any method blank, the laboratory was required to isolate the source of 
contamination and reanalyze associated samples.
    Multiple aliquots of each sample were collected in order to 
accommodate the numerous analyses required. The multiple aliquots were 
split from a homogenized sample and, to the extent practicable, 
contained identical concentrations of oil and grease. Within each of 
the three different solvent procedures and two modified methods (413.1 
and 5520F), it was expected that the relative standard deviation (RSD) 
of the triplicate measurements would be less than or equal to 10 
percent for those results at or above 25 mg/L and less than or equal to 
20 percent for those results less than 25 mg/L. The evaluating 
laboratory was required to notify EPA if the triplicate results 
exceeded these RSDs.
    Addition of these QC requirements and data quality objectives to 
the usual method protocol, and careful monitoring of the analytical 
techniques ensured that reliable data were produced.
    Alternative analytical techniques were also evaluated. These 
techniques were performed voluntarily by manufacturers of various 
devices on splits of samples collected as part of Phase II. EPA 
supplied additional volumes of each sample collected during the Phase 
II study to a number of vendors that tested alternative oil and grease 
extraction and measurement techniques similar to those tested in the 
Phase I study. These included solid phase extraction using cartridges 
and disks, non-dispersive infrared spectroscopy, and immunoassay.
    Evaluation of Phase II data led to the conclusion that the results 
generated when using n-hexane and cyclohexane were statistically 
equivalent to one another, but that these results were significantly 
different from results generated when using Freon-113 as the extraction 
solvent. These findings were consistent with the Phase I study 
conclusion that, when all sample matrices are collectively considered, 
none of the solvents that were evaluated was statistically equivalent 
to Freon-113. Specifics of the study design, results, and conclusions 
are included in the Report of EPA Efforts to Replace Freon for the 
Determination of Oil and Grease and Total Petroleum Hydrocarbons: Phase 
II, April 1995, that is included in the docket.
    The decision of which alternative solvent was best suited for the 
new method was therefore based on logistical analytical considerations, 
of which the primary factor was the difference between the boiling 
points of n-hexane (69  deg.C) and cyclohexane (81  deg.C). Based on 
laboratory comments regarding the extensive amount of time required to 
evaporate cyclohexane, n-hexane was determined to be a more suitable 
replacement for Freon-113.
    Evaluation of vendor data was limited to the SPE disk and column 
extraction techniques with gravimetric determination, and demonstrated 
that results from both of the SPE techniques were not statistically 
equivalent to 

[[Page 1733]]
results produced by either Freon-113 or n-hexane using separatory 
funnel extraction and gravimetric determination.
    Results from the non-dispersive infrared and immunoassay analyses 
were not considered for this proposal because they represent completely 
different determinative techniques. EPA is, however, planning to 
further evaluate these techniques and consider other promising 
procedures in subsequent studies.
    Though written as a separatory funnel extraction procedure, Method 
1664 allows the use of alternative extraction and concentration 
techniques, such as SPE, under the performance-based option, provided 
that these techniques produce results that meet the specifications in 
Method 1664 when tested using reference standards and, when used for 
compliance monitoring, produce results equivalent to results produced 
by Method 1664 on the specific discharge to which they are to be 
applied.
    The Agency solicits additional comparative data and information on 
SPE techniques and other alternative extraction and concentration 
techniques, and on the proposal to allow these techniques under the 
performance-based option in Method 1664. EPA is particularly interested 
in comparative data produced from alternative techniques and separatory 
funnel extraction with gravimetric determination when both techniques 
are concurrently applied to a given wastewater discharge.
    The final product of Phase II was Method 1664, which uses n-hexane 
as the extraction solvent. Between April and September, 1994, the March 
29, 1994 draft version of the Method was distributed extensively at 
several conferences and workshops and in response to requests to EPA.
    EPA encouraged reviewers to submit any questions, clarifications, 
data, or issues for consideration in updating the Method for this 
proposal. As part of the effort to collect information from interested 
parties, a questionnaire pertaining to Phase II of the Freon 
Replacement Study and the content of Method 1664 was distributed on May 
4, 1994 at EPA's 17th Annual Conference on Analysis of Pollutants in 
the Environment. EPA also collected information from studies performed 
by industry representatives, including a report produced by the 
American Petroleum Institute titled Method Development and Freon-113 
Replacement in the Analysis of Oil and Grease in Petroleum Industry 
Samples, and a presentation delivered by Dave Clampitt from the Uniform 
& Textile Service Association at EPA's 17th Annual Conference on 
Analysis of Pollutants in the Environment titled Impact of Detergents 
on the Determination of Oil and Grease by Gravimetric and Infra-red 
Analysis. Comments received as a result of these efforts were reviewed 
and considered when revising Method 1664 to produce the April 1995 
version being proposed today. These comments are included in the 
docket.
    The quality control acceptance criteria in Method 1664 were derived 
from the Phase II results and the results from an interlaboratory study 
conducted by 11 laboratories belonging to the Twin City Round Robin 
Group. In addition, Method Detection Limit (MDL) studies were performed 
to determine the MDL and minimum level (ML) specifications included in 
the version of the Method being proposed today. Details of these 
studies are included in the docket as part of the document titled 
Report of the Method 1664 Validation Studies, April 1995.

B. N-Hexane as the Extraction Solvent

    In the process of deciding upon the most suitable extraction 
solvent for replacement of Freon-113, EPA considered the potential 
effects of the new solvent on compliance monitoring, logistics, and 
health and safety concerns. Of all the solvents evaluated in the Freon 
Replacement Study, n-hexane was the most appropriate choice for the 
following reasons: (1) It had been previously used as the extraction 
solvent for permit compliance analysis of oil and grease and TPH prior 
to the advent of Freon-113, (2) EPA Phase I and Phase II studies 
indicated that n-hexane produces results that are as or more comparable 
to Freon-113 results than other solvents (although no solvent produced 
results exactly equivalent to Freon-113), and (3) the Phase II study 
showed that there was no significant difference in results produced by 
n-hexane and Freon-113 for the analysis of reagent water samples spiked 
with reference standards. In addition, a comparison of the Phase I and 
Phase II data suggests that any change in oil and grease concentration 
that may result from using n-hexane instead of Freon-113 would be 
overshadowed by the variability that was observed in the currently 
approved Freon methods that did not impose these thorough QC 
requirements.
    Once the solvent choices had been narrowed to cyclohexane and n-
hexane, and the results of Phase II indicated that both solvents 
produced equivalent results, the decision was based on more pragmatic 
issues. Of concern was the neurotoxicity of n-hexane compared to 
cyclohexane and the cost of the two solvents. EPA compared the 
Occupational Safety and Health Administration (OSHA) permissible 
exposure limits (PELs) for cyclohexane and n-hexane. This comparison 
showed that n-hexane is only 1.7 times more toxic than cyclohexane and 
that the time weighted average (TWA) for n-hexane is 300 ppm, compared 
to 500 ppm for cyclohexane. TWA is defined as the average airborne 
exposure that shall not be exceeded in any 8-hour work shift of a 40-
hour work week. Based on these figures, the toxicity of n-hexane is not 
appreciably higher than that of cyclohexane and can be minimized by 
implementing effective safety controls and procedures in the 
occupational setting.
    An examination of the relative costs of n-hexane and cyclohexane 
revealed that cyclohexane costs approximately 17 percent more than n-
hexane from the four suppliers surveyed.
    Based on the solvent evaporation time issue presented in the 
discussion on Phase II of the Freon Replacement Study and the cost 
considerations detailed above, n-hexane was selected over cyclohexane 
as the solvent to replace Freon-113.

III. Summary of Proposed Rule

A. Introduction

    This proposed rule would allow the use of EPA Method 1664 for the 
determination of ``oil and grease'' and ``total petroleum 
hydrocarbons'', and would withdraw approval of EPA Method 413.1 and 
Standard Method 5520B. Though on May 10, 1995, a global exemption for 
laboratory and analytical essential uses of CFCs was granted for the 
1996 and 1997 control periods (60 FR 24970), this proposed rule will 
nonetheless provide for the elimination of the use of Freon-113 because 
of the unacceptable inconsistencies that would be created by allowing 
analytical methods employing two different solvents for determination 
of oil and grease. The proposed replacement method, Method 1664: N-
Hexane Extractable Material (HEM) and Silica Gel Treated N-Hexane 
Extractable Material (SGT-HEM) by Extraction and Gravimetry (Oil and 
Grease and Total Petroleum Hydrocarbons), April 1995, is a gravimetric 
procedure applicable to aqueous matrices for the determination of n-
hexane extractable material and silica gel treated n-hexane extractable 
material (oil and grease and total petroleum hydrocarbons, 
respectively). The proposed method contains more 

[[Page 1734]]
thorough QA/QC procedures than the Freon methods proposed for 
withdrawal.
    ``Oil and Grease'' is a conventional pollutant defined in the Clean 
Water Act and codified at 40 CFR 401.16. The term ``n-hexane 
extractable material'' (HEM) reflects the fact that this method can be 
applied to materials other than oils and greases. Similarly, the term 
``silica gel treated n-hexane extractable material'' (SGT-HEM) reflects 
that this method can be applied to materials other than aliphatic 
petroleum hydrocarbons that are not adsorbed by silica gel.
    Method 1664 is a performance-based method that allows alternative 
extraction and concentration techniques, provided that equivalent 
performance can be demonstrated using reference standards and by 
complying with all performance specifications given in the Method.

B. Summary of Proposed Method 1664

    For determination of n-hexane extractable material (HEM), samples 
are acidified to pH <2 and serially extracted three times with 30-mL 
portions of n-hexane in a separatory funnel. The extract is filtered 
through sodium sulfate to remove residual water, and the solvent is 
evaporated by heating with a steam or water bath. The HEM that remains 
is weighed and the concentration calculated in mg/L.
    For determination of silica gel treated n-hexane extractable 
material (SGT-HEM), the HEM is redissolved in n-hexane, and silica gel 
is added to remove adsorbable materials. The amount of silica gel added 
is proportional to the amount of HEM. The solution is filtered to 
remove the silica gel, the solvent is evaporated by heating, and the 
SGT-HEM is weighed to produce the concentration in mg/L.

C. Method Quality Control

    The quality control criteria incorporated into the Method exceeds 
and improves upon that of the currently approved 40 CFR Part 136 oil 
and grease methods, and is consistent with the 40 CFR 136 Appendix A 
protocol for determination of organic analytes. Initial demonstrations 
of laboratory capability are required and consist of (1) a method 
detection limit (MDL) study to demonstrate that the laboratory is able 
to achieve the MDL and ML specified in the Method, and (2) an initial 
precision and recovery (IPR) test consisting of the analysis of four 
spiked reagent water samples to demonstrate the laboratory's ability to 
generate acceptable precision and accuracy.
    An important component of these and other QC tests required in 
Method 1664 is the use of hexadecane and stearic acid as the reference 
standards for spiking. Hexadecane was chosen to simulate petroleum 
hydrocarbons; stearic acid was chosen to simulate animal fats and 
detergents, and serves to test the effects of the silica gel procedure. 
The use of standards of known composition and purity, which are not a 
requirement of the currently approved gravimetric methods for the 
determination of oil and grease, allows for more accurate determination 
of recovery and precision and minimizes variability that may be 
introduced from spiking with substances such as Wesson oil, #2 fuel 
oil, mineral oil, etc. that are comprised of unknown proportions of 
substances.
    Routine quality control consists of an initial two point 
calibration of the analytical balance, and the following tests that 
must accompany each analytical batch (the set of samples extracted at 
the same time, to a maximum of 10 samples):
     Analysis of a matrix spike (MS) and matrix spike duplicate 
(MSD) to demonstrate method accuracy and precision, and to monitor 
matrix interferences. Hexadecane and stearic acid are the reference 
standards used for spiking.
     Analysis of a laboratory blank to demonstrate freedom from 
contamination.
     Verification of calibration of the analytical balance, to 
demonstrate that measurements are in control.
     Analysis of an ongoing precision and recovery (OPR) sample 
to demonstrate that the analysis system is in control and acceptable 
precision and accuracy is being maintained with each analytical batch. 
The OPR sample consists of reagent water spiked with hexadecane and 
stearic acid. It is the equivalent of one of the IPR samples.
    The laboratory is required to meet the acceptance criteria listed 
in Method 1664 for these quality control tests and is encouraged to 
monitor performance over time to identify and anticipate problems or 
improvements to the procedure.
    Aside from the use of a solvent other than Freon-113, the most 
significant difference between Method 1664 and approved and existing 
methods used for oil and grease and petroleum hydrocarbons 
determinations is that Method 1664 contains an extensive QA/QC program 
that allows the data user to evaluate the quality of the results. This 
promotes a consistent, careful evaluation of the data generated that 
increases the reliability of results produced by HEM and SGT-HEM 
determinations, and provides a means for laboratories and data users to 
monitor analytical performance, thereby providing a basis for sound, 
defensible data.

D. Performance Based Approach

    To allow for advances in technology and reductions in the cost of 
analyses, Method 1664 is performance-based. Alternate extraction and 
concentration procedures are permitted as long as the equivalency 
procedures in the Method are followed and all QC acceptance criteria 
are met. The equivalency procedures consist of performing the IPR test 
using reference standards to demonstrate that the results produced with 
the modified procedure meet the specifications in Method 1664. In 
addition, if the detection limit will be affected by the modification, 
performance of an MDL study is required to demonstrate that the 
modified procedure can achieve an MDL less than or equal to the MDL in 
the Method or, for those instances in which the regulatory compliance 
level is greater than the Minimum Level in the Method, one-third the 
regulatory compliance level, whichever is higher.
    If the performance-based option is to be applied to analyses for 
compliance monitoring, the discharger must demonstrate that the 
modified method produces results equivalent to those produced by Method 
1664 for each specific discharge. The reason that this additional 
demonstration over and above the demonstration of equivalency with 
reference standards is required is that the possibility exists that 
Method 1664 and the modified method may produce equivalent results with 
reference standards but not produce equivalent results when the 
discharge is analyzed. Both Phase I and Phase II of the Freon 
Replacement Study demonstrated that results produced by other solvents 
are not equivalent to the results produced by Freon-113 when 
comparative tests are performed on discharges. EPA is concerned that 
the amount of material extracted from a discharge by a modified method 
will not be equivalent to the amount of material extracted by Method 
1664. If the amount of material extracted is less when the modified 
method is used, the amount discharged could be greater before a 
violation would occur. Similarly, if the amount of material extracted 
is greater when the modified method is used, the amount discharged 
would need to be less to prevent a violation. The requirement to verify 
the equivalence of the modified method to Method 1664 assures that the 
modified method and 

[[Page 1735]]
Method 1664 exhibit equivalent performance on the specific discharge.
    For those instances in which the results from the equivalence study 
of field samples are below the Minimum Level, and the test of the 
modified method is passed for spikes of reference standards into 
reagent water, the modified method is deemed to be equivalent to this 
method for determining HEM and/or SGT-HEM on that specific discharge. 
This allowance is based on the reasoning that the level of material in 
this discharge will be so low that it is unlikely a violation will ever 
occur with this discharge and, consequently, small differences in the 
amount measured with the modified method as compared to Method 1664 
will be negligible.
    The procedure required to demonstrate equivalency consists of the 
following: (1) Two sets of four one-liter aliquots of a specific 
discharge are collected for analysis--one set is analyzed according to 
Method 1664--the other set is analyzed according to the modified 
procedure, (2) the average percent recovery of HEM and/or SGT-HEM is 
calculated for each set of four analyses, and (3) the average percent 
recovery using the modified procedure must be 79-114 percent of the 
average percent recovery produced by Method 1664 for HEM and 66-114 
percent of the average percent recovery produced by Method 1664 for 
SGT-HEM. Unless these criteria are met, the modified procedure cannot 
be used for compliance monitoring purposes.
    Whether or not the modified procedure is applied to compliance 
monitoring, all modifications to the Method must be thoroughly 
documented and the documentation must be maintained in the format 
specified in Method 1664.

IV. Method Validation and Precision and Recovery of the Proposed Test 
Method

    The version of Method 1664 being proposed today is the product of 
revisions to the March 29, 1994 draft, and the October 1994 and January 
1995 versions, and reflects consideration of numerous peer review 
comments, survey results, data from industry studies, results from an 
interlaboratory method validation study, and results from several EPA 
single-laboratory method detection limit (MDL) studies.

A. Precision and Recovery Studies

    The interlaboratory method validation study conducted by EPA 
consisted of tests of initial precision and recovery (IPR) and ongoing 
precision and recovery (OPR) in twelve different analytical testing 
laboratories. Data produced in this study were used to derive the QC 
acceptance criteria for precision and recovery that are specified in 
Table 1 of Method 1664. Details of the analyses and results are 
described in a document titled Report of the Method 1664 Validation 
Studies, April 1995.
    One of the twelve laboratories participating in the validation 
study performed the QC analyses, which included one set of IPR analyses 
and 30 OPR analyses, as part of the n-hexane, cyclohexane, and Freon-
113 comparisons for Phase II of the Freon Replacement Study. Since many 
of the techniques incorporated into Method 1664 evolved as this 
evaluating laboratory performed analyses under Phase II of the Freon 
Replacement Study, some of the work was developmental in nature. For 
example, the decision to use hexadecane and stearic acid as spiking 
standards required determination of an appropriate concentration as 
well as an appropriate solvent for the stock solution.
    Another issue was the applicability of the silica gel extraction 
procedure to HEM concentrations in excess of 100 mg/L. The adsorptive 
capacity of silica gel needed to be studied in order to determine the 
amount of silica gel required to adsorb increasing concentrations of 
HEM. In addition, it was necessary to determine an appropriate cutoff 
for the maximum amount of silica gel that realistically could be used. 
Through a series of tests, it was determined that if more than 30 g of 
silica gel is used, the potential for contamination from substances in 
the silica gel increases.
    Analysis of IPRs prior to sample analysis and continuing evaluation 
of the analytical system through OPR analyses were necessary to 
evaluate the potential effects of all procedural changes implemented as 
a result of this developmental work.
    Results from the evaluating laboratory's analysis of real world 
samples supports the Method 1664 criteria derived from the method 
validation data. Because each field sample was analyzed in triplicate, 
the standard deviation of the replicate values could be derived. The 
mean relative standard deviation (RSD) across all analyses was 11.5 
percent, thereby demonstrating the precision of Method 1664 on real 
world sample matrices.
    The other eleven laboratories involved in method validation, 
working cooperatively as part of the Twin City Round Robin (TCRR) 
Group, performed IPR and OPR analyses for the determination of HEM by 
Method 1664. In addition to the QC analyses, this study consisted of 
the analysis of two sets of samples, one from a petroleum source and 
the other from a nonpetroleum source, in triplicate, for HEM. The mean 
RSD of the results across all laboratories and all samples was 9.5 
percent, further demonstrating that Method 1664 is capable of producing 
precise results on real world samples. Results and evaluation of the 
TCRR study, including field sample analyses, are presented in the 
document titled Report of the Method 1664 Validation Studies, April 
1995.
    TCRR study participants submitted comments on the method, most of 
which focused on difficulties related to extracts containing excessive 
amounts of water and the longer time required for the evaporation of n-
hexane. These issues have been addressed in the revision of Method 1664 
being proposed today, the former by recommending more careful 
separation of the aqueous and solvent phases to avoid carryover of the 
water into the extract and that more sodium sulfate be used in the 
filtering process, and the latter by allowing the use of either a water 
bath or steam bath set at a temperature that results in evaporation of 
the solvent within 30 minutes.
    Most laboratories in the interlaboratory study did not encounter 
difficulties with the analysis of IPR and OPR samples and were able to 
achieve acceptable recoveries of hexadecane and stearic acid. 
Statistical evaluation of the results from all twelve laboratories 
produced few outliers, indicating that Method 1664 is a reproducible 
procedure sufficiently reliable to be used by a variety of 
laboratories.

B. Development of Quality Control Acceptance Criteria

    As stated above, data from the TCRR interlaboratory study were 
combined with data from EPA's data gathering in Phase II to produce 
performance specifications in the form of quality control (QC) 
acceptance criteria for Method 1664. The development of these criteria 
are described in the Report of the Method 1664 Validation Studies, 
April 1995, included in the docket. Criteria were developed for initial 
precision and recovery (IPR), ongoing precision and recovery (OPR), and 
recovery of hexadecane and stearic acid spiked into samples (matrix 
spikes) for both HEM and SGT-HEM. For HEM, the IPR and OPR acceptance 
criteria were constructed using analysis of variance (ANOVA) 
statistics. The criteria for recovery of a matrix spike (MS) and for 
the relative percent difference between an MS and a matrix spike 
duplicate 

[[Page 1736]]
(MSD) were transferred from the IPR and OPR criteria, since neither the 
TCRR study or EPA's data gathering efforts required the spiking of 
field samples. EPA believes that this transfer is acceptable because 
the determinative technique in Method 1664 is gravimetry, which is not 
susceptible to interferences, and because the treated effluent to which 
Method 1664 is to be applied in monitoring is nearly identical to the 
reagent water used in the IPR and OPR tests. EPA used a similar 
transfer of data for development of specifications for acceptance 
criteria in the organic methods promulgated at 40 CFR Part 136, 
Appendix A.
    For SGT-HEM, EPA received results from only two laboratories. EPA 
used these data to construct preliminary acceptance criteria for SGT-
HEM and widened these preliminary criteria to those of HEM in those 
instances in which the calculated SGT-HEM criteria were more stringent 
than those for HEM. The acceptance criteria were widened based on the 
knowledge that the determination of SGT-HEM follows the determination 
of HEM in Method 1664, and therefore the results for SGT-HEM is likely 
to be at least as variable as results for HEM.
    EPA solicits data on the variability of the determination of HEM 
and SGT-HEM, particularly data from interlaboratory studies using 
either the March 29, 1994 version of Method 1664 that was distributed 
at various conferences, the October 1994 or January 1995 versions of 
Method 1664, or the April 1995 version that is cited in today's 
proposed rule and which is included in the docket.

C. Method Detection Limit Studies

    To date, five single-laboratory method detection limit (MDL) 
studies have been performed as part of the effort to determine MDLs and 
MLs for HEM and SGT-HEM. Results of these studies are detailed in the 
document titled Report of the Method 1664 Validation Studies, April 
1995. The MDL is defined as the minimum concentration of a substance 
that can be measured and reported with 99 percent confidence that the 
analyte concentration is greater than zero. To determine the MDL, the 
laboratories were required to follow the procedure in Appendix B to 40 
CFR Part 136. This procedure consists of the analysis of seven aliquots 
of reagent water that are spiked with the analyte(s) of interest. For 
EPA's MDL studies, the hexadecane and stearic acid specified in the 
quality control tests in Method 1664 were used. Spike levels were in 
the range of one to five times the estimated detection limit. The MDL 
is calculated by multiplying the standard deviation of the seven 
replicate analyses by the Student's t value for (n-1) degrees of 
freedom, where n equals the number of replicates. The Student's t value 
for seven replicates is 3.143.
    The Minimum Level is defined as the level at which the entire 
analytical system produces a recognizable signal and an acceptable 
calibration point, and is determined by multiplying the MDL by 3.18 and 
rounding the resulting value to the number nearest to (1, 2, or 5)  x  
10n, where n is an integer. The value ``3.18'' represents the 
ratio between the Student's t multiplier used to determine the MDL 
(3.143) and the 10 times multiplier used in the American Chemical 
Society (ACS) Limit of Quantitation (LOQ) (i.e., 10  3.143 = 
3.18). For example, if the calculated MDL is 1.7, the ML will be equal 
to 1.7 times 3.18, which equals 5.1. Rounding to the number nearest to 
(1, 2, or 5)  x  10n establishes the ML at 5.0.
    The first MDL study was performed in a commercial laboratory by an 
analyst at the Ph.D. level who has more than 20 years of experience in 
the determination of oil and grease and TPH. This study yielded an MDL 
of 0.91 mg/L and a resultant ML of 2 mg/L for HEM and an MDL of 1.6 mg/
L and a resultant ML of 5 mg/L for SGT-HEM.
    Based on the disparity between the results obtained by this 
laboratory and the lower limit of the range in Method 413.1, it was 
decided that a second MDL study should be conducted in another 
commercial laboratory to verify the values obtained in the first study.
    The second MDL study was also performed by a laboratory experienced 
in the determination of oil and grease and TPH, though the analysts 
performing the study were not at the Ph.D. level. In order to move 
expeditiously, the laboratory was required to perform the second MDL 
study within 24 hours. An MDL of 5.4 mg/L and an ML of 20 mg/L for HEM, 
and an MDL of 2.6 mg/L and an ML of 10 mg/L for SGT-HEM was determined 
in the second MDL study.
    The second laboratory was contacted to determine if they 
encountered difficulties in performing the study. They stated that the 
results were the best that could be obtained under the imposed 24 hour 
turn-around time constraint, and that they believed they could achieve 
lower MDLs given more time. Based on these circumstances, the Agency 
decided that the MDLs to be included in the October version of Method 
1664 should be those representing the better performing laboratory. 
Therefore, the MDL and associated ML values from the original Method 
1664 MDL study were incorporated into the October 1994 revision of the 
Method.
    The high results produced in the second MDL study brought into 
question the reasonableness and effect of requiring a 24-hour 
turnaround. As a result, the second laboratory performed another MDL 
study (MDL study #3), this time without the turnaround constraint, and 
with the analytical objective to confirm the MDLs/MLs that had been 
obtained in the first MDL study. An MDL of 2.4 mg/L and an associated 
ML of 10 mg/L for HEM, and an MDL of 1.7 mg/L and an associated ML of 5 
mg/L for SGT-HEM were obtained from this third MDL study. Although 
closer to the MDL and ML for HEM obtained in the first MDL study, the 
ML of 10 mg/L for HEM is still above the equivalent level in Method 
413.1, and the result for SGT-HEM, the more complex procedure, is still 
less than the result for HEM.
    From these results, the Agency concluded that the MDLs/MLs for HEM 
and SGT-HEM produced in the first MDL study are self-consistent, 
whereas the results produced in the second and third MDL studies are 
not. Therefore, the MDL and ML limits specified in the January 1995 
version of the Method were those from the first MDL study.
    The Agency still needed to address the issue that the HEM MDL 
values in both the October 1994 and the January 1995 versions of Method 
1664 had not been verified with follow-up MDL studies. In contrast, a 
comparison of SGT-HEM results shows that the MDL/ML for SGT-HEM from 
the third MDL study supports the first MDL study results for SGT-HEM. 
(Both the first and third MDL studies produced an ML of 5 mg/L for SGT-
HEM.)
    To verify the HEM MDL and ML values specified in the October 1994 
and January 1995 versions of Method 1664, which were the results 
obtained in MDL study #1, the laboratory that performed this MDL study 
conducted another study (MDL study #4). As with MDL study #1, the same 
Ph.D. level chemist with extensive analytical experience performed the 
analyses. Because the spike level in MDL study #1 was greater than five 
times the resulting MDL, the spike level was lowered to 5 mg/L. An MDL 
of 0.88 mg/L, with a resulting ML of 2 mg/L was obtained, thereby 
supporting the original MDL results.
    In response to comments received from laboratories and other 
interested parties regarding the difficulties encountered when 
attempting to achieve the HEM MDL of 0.91 mg/L specified in the October 
1994 and January 1995 versions of Method 1664, 

[[Page 1737]]
and because most technicians performing HEM analysis for commercial 
laboratories will not have the experience or qualifications of the 
Ph.D. level chemist who performed MDL studies 1 and 4, an analyst with 
a bachelor's degree and one month's laboratory experience performed 
another HEM MDL study at this laboratory. The results of MDL study #5 
were an HEM MDL of 1.4 mg/L and a resulting ML of 5 mg/L.
    EPA has concluded that the MDL appropriate for Method 1664 should 
be representative of a better performing laboratory. However, to 
realistically address the qualifications of the laboratory personnel 
most likely to perform this procedure, the MDL should reflect the 
results obtained when using qualified, but not Ph.D. level, personnel. 
Therefore, the HEM MDL specified in the April 1995 version of Method 
1664 (the version being proposed) is 1.4 mg/L and the HEM ML is 5 mg/L. 
Unchanged from the January 1995 version of Method 1664, the SGT-HEM MDL 
is 1.6 mg/L and the SGT-HEM ML is 5 mg/L.
    EPA solicits comment on the appropriateness of these MDLs and data 
from other MDL studies conducted with the goal of achieving an MDL of 1 
mg/L or less for HEM and SGT-HEM.

V. Withdrawal of Currently Approved Methods

    The Clean Air Act Amendments of 1990 (CAAA) established schedules 
for phasing out the production and importation of CFCs in the U.S. 
Pursuant to section 606, production of most class I substances, 
including Freon, is phased-out as of January 1, 1996, except for a few 
exemptions for essential uses. Existing supplies may be used after that 
date, but the substances will become increasingly scarce and costly 
over time. On May 10, 1995, a global exemption for laboratory and 
essential analytical uses of CFCs was granted for the 1996 and 1997 
control periods (60 FR 24970). This exemption explicitly allows for the 
production of CFCs for laboratory use through December 31, 1997. 
Therefore, it would be possible to allow continued use of the currently 
approved analytical methods that employ CFCs along with the use of 
Method 1664.
    EPA has considered allowing continued use of the currently approved 
methods, but believes that unacceptable conflicts would be created by 
allowing the simultaneous use of oil and grease methods that employ 
different extraction solvents. As is detailed above, EPA's Freon 
Replacement Studies indicated that no solvent produces results 
sufficiently equivalent to the results produced by Freon-113. By 
allowing two or more methods that employ different solvents, the 
possibility exists that a regulatory authority and a discharger could 
produce different results for the same analyte in the same sample. 
Indeed, the same analyst testing the same sample could produce 
unacceptably different results using the different methods. If one of 
these results showed a permit violation and the other did not, an 
unfair conflict would result.
    As is also detailed above, Method 1664 contains extensive quality 
control procedures to assure that precise and accurate results are 
produced. If use of the currently approved methods is continued, the 
possibility also exists that analytical results could indicate a permit 
violation due to the greater variability of results produced by these 
methods when compared to the proposed Method 1664. For example, if the 
permit limit is 20 mg/L and the true concentration of oil and grease in 
the discharge is slightly less than this limit, Method 1664 is more 
likely to produce a result closer to the true value than the currently 
approved methods because of the improved precision of the Method.
    The conflict between results obtained using the existing approved 
methods and results obtained using the proposed Method 1664 arises 
because oil and grease is a ``method-defined'' parameter. Much like 
biochemical oxygen demand measured over five days (``BOD5''), and 
total suspended solids (``TSS''), which measures the amount of non-
filterable material suspended in water, the quantification of oil and 
grease depends on the procedures used to measure the parameter in the 
first place. The analytical result is dependent on how the measurement 
is conducted. In the case of BOD5, the sample pH, the seed 
quality, the incubation time and temperature, and other factors define 
how much BOD occurs. In the case of TSS, the sample homogeneity, the 
filter type and pore size, the drying time and temperature, and other 
factors determine the amount of solids that will be measured. In the 
specific case of oil and grease, one portion of the test sample 
preparation procedure, the addition of a specific solvent, defines how 
much ``oil and grease'' will be extracted. The oil and grease parameter 
is that material which is extracted by the solvent and not lost during 
solvent drying or evaporation.
    Given these concerns, and to avoid other potential conflicts, EPA 
is proposing to withdraw approval of the use of methods for oil and 
grease determination that are currently promulgated at 40 CFR Part 136.
    In an effort to provide for the use and depletion of existing 
laboratory stocks of Freon-113, EPA plans to implement the withdrawal 
of the existing Freon methods no sooner than six months after the final 
rule is published in the Federal Register. In this scenario, Freon-113 
and the currently approved methods would continue to be used until the 
implementation date. N-hexane and Method 1664 would be required on that 
date and thereafter. EPA seeks comment on the desirability of this 
scenario, alternate scenarios, and whether the 6-month period is 
sufficient or, if insufficient, the length of the desired period. EPA 
also seeks comment as to whether the 6-month period is too long, in 
that persons and organizations affected by this rule may desire to 
switch to n-hexane sooner to reduce the costs associated with the 
purchase of Freon-113. When submitting comments on this issue, please 
indicate the amount of Freon-113 being used by your organization for 
oil and grease determinations using the currently approved 40 CFR Part 
136 methods so that EPA can assess the number of parties affected and 
the extent of the effect.

VI. Regulatory Requirements

A. Regulatory Impact Analysis

    Executive Order 12866 requires that regulatory agencies prepare an 
analysis of the regulatory impact of major rules. Major rules are 
defined as those likely to result in: (1) An annual cost to the economy 
of $100 million or more; or (2) a major increase in costs or prices for 
consumers or individual industries; or (3) significant adverse effects 
on competition, investment, innovation, or international trade. This 
regulation is not a major regulation for the reasons discussed below.
    The impact of this proposed regulation will be far less than $100 
million annually. Laboratories are switching to CFC substitutes (or 
substitute methods) as CFCs become more costly due to restriction in 
supply and due to the excise tax that, as a result of the 1989 and 1990 
Budget Reconciliation Acts, is imposed on all ozone-depleting chemicals 
listed in the Montreal Protocol and the 1990 CAAA. Thus, the true cost 
of this regulation is the difference in expense of switching to CFC 
substitutes now as opposed to later. The Agency believes that these 
increased transitional costs will be minimal for the following reasons:
    First, laboratory testing is a very small part of Freon-113 
consumption (less 

[[Page 1738]]
than 1 percent) and the testing required by EPA is only a fraction of 
this total. EPA estimates that the total market for Freon-113 for 
laboratory use is less than $2 million annually.
    Second, this rule is not likely to cause a major increase in costs 
or prices for individuals or consumers. Laboratories may experience 
some increase in costs due to longer testing procedures because of the 
increased number of sample manipulations and the additional quality 
control in the method. However, the price for n-hexane is actually 
cheaper per pound than the CFCs and this difference may increase as CFC 
production is reduced and supply becomes more limited.
    Third, this regulation is unlikely to cause significant adverse 
effects on competition, investment, innovation, or international trade. 
As noted above, laboratory use of these products is estimated to be 
much less than 1 percent of the total market for these products. 
Further, in some cases this proposed rule and notice would result in a 
switch back to procedures commonly used in the 1970s, which did not 
have a significant impact on competition, investment, or trade at that 
time.
    On March 9, 1995, this proposal was granted a waiver from review by 
the Office of Management and Budget.

B. Unfunded Mandates

    Under Section 202 of the Unfunded Mandates Reform Act of 1995, 
signed into law on March 22, 1995, EPA must prepare a statement to 
accompany any rule where the estimated costs to State, local, or tribal 
governments, or to the private sector, will be $100 million or more in 
any one year. Under Section 205, EPA must select the most cost-
effective and least burdensome alternative that achieves the objective 
of the rule and is consistent with statutory requirements. Section 203 
requires EPA to establish a plan for informing and advising any small 
governments that may be significantly impacted by the rule.
    EPA estimates that the costs to State, local, or tribal 
governments, or to the private sector, from this rule will be less than 
$100 million. This rulemaking should have minimal impact on the current 
regulatory burden imposed on permittees because the rulemaking will 
simply replace an existing test procedure with a new procedure. EPA has 
determined that an unfunded mandates statement is therefore 
unnecessary. Similarly, the method in today's rule does not establish 
any regulatory requirements that might significantly or uniquely affect 
small governments.

C. Regulatory Flexibility Act

    Pursuant to the Regulatory Flexibility Act, 5 U.S.C. 601, whenever 
an agency is required to publish a notice of rulemaking for any 
proposed or final rule, it must prepare and make available for public 
comment a Regulatory Flexibility Analysis that describes the effect of 
the rule on small entities (i.e., small businesses, small 
organizations, and small governmental jurisdictions). This analysis is 
unnecessary if the Agency's Administrator certifies that the rule will 
not have a significant economic effect on a substantial number of small 
entities.
    This proposed rule will not have a significant economic impact on a 
substantial number of small facilities. This regulation simply approves 
an analytical technique to be available for use by all laboratories.

D. Paperwork Reduction Act

    This rule contains no requests for information and is, therefore, 
exempt from the requirements of the Paperwork Reduction Act, 44 U.S.C. 
3501 et seq.

VII. Materials Proposed for Incorporation by Reference Into 40 CFR 
Part 136

    1. Method 1664: N-Hexane Extractable Material (HEM) and Silica Gel 
Treated N-Hexane Extractable Material (SGT-HEM) by Extraction and 
Gravimetry (Oil and Grease and Total Petroleum Hydrocarbons), April 
1995, Document No. EPA-821-B-94-004b, available from the EPA Water 
Resource Center, Mail Code RC-4100, 401 M Street, S.W., Washington, 
D.C. 20460, phone: 202/260-7786 or 202/260-2814.

VIII. Request for Comments

    EPA requests public analysis, comments, and information on the 
replacement of Freon-113 with n-hexane, the utility of Method 1664 for 
monitoring, the QC acceptance criteria in Method 1664, the MDL and ML 
levels, the performance-based option criteria, and the 6-month 
implementation scenario.

List of Subjects in 40 CFR Part 136

    Environmental protection, Reporting and recordkeeping requirements, 
Water pollution control, Incorporation by reference.

    Dated: December 12, 1995.
Carol M. Browner,
Administrator.

    In consideration of the preceding, USEPA proposes to amend 40 CFR 
Part 136 as follows:

PART 136--[AMENDED]

    1. The authority citation of 40 CFR Part 136 continues to read as 
follows:

    Authority: Secs. 301, 304(h), 307, and 501(a) Pub. L. 95-217, 
Stat. 1566, et seq. (33 U.S.C. 1251, et seq.) (The Federal Water 
Pollution Control Act Amendments of 1972 as amended by the Clean 
Water Act of 1977 and the Water Quality Act of 1987), 33 U.S.C. 1314 
and 1361; 86 Stat. 816, Pub. L. 92-500; 91 Stat. 1567, Pub. L. 92-
217; Stat. 7, Pub. L. 100-4 (The ``Act'').

    2. In Sec. 136.3(a), Table 1B.-List of Approved Inorganic Test 
Procedures, is proposed to be amended by revising entry 41. Oil and 
grease-Total recoverable; by adding an entry for petroleum 
hydrocarbons, total recoverable; and by adding a note to Table 1B to 
reference Method 1664 to read as follows:


Sec. 136.3  Identification of test procedures.

* * * * *

                              Table 1B.--List of Approved Inorganic Test Procedures                             
----------------------------------------------------------------------------------------------------------------
                                                                            Reference (Method No. or page)      
                                                                    --------------------------------------------
                                                                                Std.                            
                    Parameter, units and methods                      EPA 1,  methods                           
                                                                        35      18th     ASTM    USGS2    Other 
                                                                                Ed.                             
----------------------------------------------------------------------------------------------------------------
                                                                                                                
      *                   *                   *                   *                   *                   *     
                                                           *                                                    
41. Oil and grease--Total recoverable, mg/L; Gravimetric                                                        
 (extraction)......................................................   XX1664                                    
----. Petroleum hydrocarbons--Total recoverable; mg/L; Gravimetric                                              
 (extraction)......................................................   XX1664                                    
                                                                                                                

[[Page 1739]]
                                                                                                                
      *                   *                   *                   *                   *                   *     
                                                           *                                                    
----------------------------------------------------------------------------------------------------------------
XX Method 1664: N-Hexane Extractable Material (HEM) and Silica Gel Treated N-Hexane Extractable Material (SGT-  
  HEM) by Extraction and Gravimetry (Oil and Grease and Total Petroleum Hydrocarbons), April 1995, Document No. 
  EPA-821-B-94-004b, can be obtained from the EPA Water Resource Center, Mail Code RC-4100, 401 M Street, S.W., 
  Washington, D.C. 20460.                                                                                       


* * * * *
    3. In Sec. 136.3(e), Table II--Required Containers, Preservation 
Techniques, and Holding Times, is proposed to be amended by adding an 
entry for petroleum hydrocarbons to read as follows:


Sec. 136.3  Identification of test procedures.

* * * * *

                   Table II.--Required Containers, Preservation Techniques, and Holding Times                   
----------------------------------------------------------------------------------------------------------------
                                                                                                        Maximum 
                    Parameter                      Container              Preservation 2,3              holding 
                                                       1                                                 time 4 
----------------------------------------------------------------------------------------------------------------
                                                                                                                
      *                   *                   *                   *                   *                   *     
                                                           *                                                    
(Add the following entry.)                                                                                      
-- --. Petroleum hydrocarbons...................           G  Cool to 4 deg. C, H2SO4 or HCL to pH<2.   28 days.
                                                                                                                
      *                   *                   *                   *                   *                   *     
                                                           *                                                    
----------------------------------------------------------------------------------------------------------------


[FR Doc. 96-877 Filed 1-22-96; 8:45 am]
BILLING CODE 6560-50-P