[Federal Register Volume 59, Number 57 (Thursday, March 24, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-5993]


[[Page Unknown]]

[Federal Register: March 24, 1994]


_______________________________________________________________________

Part IV





Environmental Protection Agency





_______________________________________________________________________



40 CFR Part 61



National Emission Standards for Hazardous Air Pollutants and Radon 
Emissions From Phosphogypsum Stacks; Final Rule
ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 61

[FRL-4849-9]

 

National Emission Standards for Hazardous Air Pollutants; 
National Emission Standard for Radon Emissions From Phosphogypsum 
Stacks

AGENCY: Environmental Protection Agency.

ACTION: Decision concerning petition for reconsideration.

-----------------------------------------------------------------------

SUMMARY: On June 3, 1992, EPA issued a final rule revising 40 CFR part 
61, subpart R, the National Emission Standard for Radon Emissions From 
Phosphogypsum Stacks (57 FR 23305, June 3, 1992). The Fertilizer 
Institute (TFI) filed a petition seeking reconsideration of the 1992 
rule pursuant to Clean Air Act section 307(d)(7)(B). This notice sets 
forth the Agency's decision concerning the TFI reconsideration 
petition.
    EPA has decided to partially grant and to partially deny the TFI 
petition for reconsideration. EPA will reconsider 40 CFR 61.205, the 
provision of the final rule which governs distribution and use of 
phosphogypsum for research and development, and the formula in 40 CFR 
61.207(d). EPA will publish a separate Federal Register notice 
convening a proceeding to reconsider these provisions shortly. EPA is 
denying the remainder of the TFI petition. In this notice, EPA 
summarizes the principal remaining objections by TFI. EPA also explains 
why these objections are not of central relevance to the outcome of the 
rule and therefore do not constitute a basis for reconsideration.

DATES: Under Clean Air Act sections 307(b)(1) and 307(d)(7)(B), TFI may 
seek judicial review of the decision by EPA to partially deny its 
August 3, 1992 petition only by filing a petition for judicial review 
in the United States Court of Appeals for the District of Columbia 
Circuit within 60 days of the date of publication of this notice in the 
Federal Register.

FOR FURTHER INFORMATION CONTACT: Jacolyn Dziuban, Air Standards and 
Economics Branch, Criteria and Standards Division (6602J), Office of 
Radiation and Indoor Air, Environmental Protection Agency, Washington, 
DC 20460, (202) 233-9474.

SUPPLEMENTARY INFORMATION:

I. Background

    Phosphogypsum is a waste resulting from wet acid phosphorus 
production. Phosphogypsum stacks are piles of waste or mines utilized 
to store and dispose of phosphogypsum. EPA issued a National Emission 
Standard for Hazardous Air Pollutants (NESHAP) applicable to radon 
emissions from such stacks in 1989, 40 CFR part 61, subpart R (54 FR 
51654, December 15, 1989). As part of that standard, EPA adopted a work 
practice requirement that all phosphogypsum be disposed in stacks, 
thereby permitting control and measurement of gaseous radon-222 which 
is emitted when radium present in the phosphogypsum decays.
    Subsequent to issuance of Subpart R, EPA received petitions for 
reconsideration from The Fertilizer Institute (TFI), Consolidated 
Minerals, Inc., and U.S. Gypsum Company. These petitioners objected to 
the requirement that all phosphogypsum be disposed and managed in 
stacks, because it operated to preclude various alternative uses of 
phosphogypsum, including use of phosphogypsum in agriculture, 
construction, and research and development. Because EPA had not fully 
considered the implications of its work practice standard for 
alternative uses, EPA agreed to convene a reconsideration proceeding in 
which the risks associated with alternative uses and the procedures 
under which alternative uses might be permitted could be evaluated (54 
FR 9612, March 7, 1989).
    Rather than setting forth one specific proposal for revision of 
subpart R, EPA requested comment on a variety of substantive issues, 
including specific types of proposed alternative uses of phosphogypsum 
and the health risks associated with these alternative uses. EPA also 
requested comment on four general options for regulation of alternative 
uses: (1) No change in the work practice requirement, (2) changing the 
definition of phosphogypsum to exclude from the work practice 
requirement material with radium-226 concentrations up to 10 
picocuries/gram (pCi/g), (3) permitting use of phosphogypsum in 
research and development on processes to remove radium from the 
phosphogypsum, and (4) permitting alternative use of phosphogypsum only 
after specific permission from EPA.
    After analyzing the risks associated with the various alternative 
uses of phosphogypsum which were proposed and evaluating the comments 
which were received, EPA issued a final rule revising subpart R (57 FR 
23305, June 3, 1992). The approach which EPA ultimately adopted was a 
hybrid of the options it had previously identified. For phosphogypsum 
use in agriculture, EPA decided that it would be impractical to require 
case-by-case approval. Based on its analysis of potential risks 
associated with long-term use of phosphogypsum in agriculture, EPA set 
a maximum upper limit of 10 pCi/g for radium-226 in phosphogypsum 
distributed for use in agriculture. Rather than excluding material at 
or below 10 pCi/g from the standard, EPA established sampling, 
measurement, and certification procedures permitting such material to 
be removed from stacks and sold for agricultural use. Based on analysis 
of potential risks associated with the research and development use, 
EPA decided to permit use of up to 700 pounds of phosphogypsum for a 
particular research and development activity. EPA also decided to adopt 
procedures permitting approval of other uses of phosphogypsum on a 
case-by-case basis.
    After EPA issued its final rule concluding the reconsideration 
proceeding and revising subpart R, The Fertilizer Institute (TFI) 
sought judicial review of the 1992 revisions of subpart R in The 
Fertilizer Institute v. Environmental Protection Agency, No. 92-1320 
(D.C. Cir.). TFI also filed a petition dated August 3, 1992 seeking 
further reconsideration of the revisions of the rule pursuant to Clean 
Air Act section 307(d)(7)(B). TFI, EPA, and ManaSota-88, another 
petitioner who sought review of the 1992 rule in ManaSota-88 v. 
Browner, No. 92-1330 (D.C. Cir.), later reached an agreement to jointly 
move the D.C. Circuit Court of Appeals to stay judicial review of the 
1992 rule, and the Court granted the motion. As part of that agreement, 
EPA agreed to make a final decision whether to grant or to deny the TFI 
petition for reconsideration by January 31, 1994. This notice sets 
forth the Agency's decision concerning the TFI reconsideration 
petition.

II. Standard for Reconsideration

    Under Clean Air Act section 307(d)(7)(B), the EPA Administrator is 
required to convene a reconsideration proceeding if: (1) The person 
raising an objection to a rule can demonstrate to the Administrator 
that it was impracticable to raise such objection within the time 
permitted for public comment or the grounds for the objection arose 
after the period for public comment, and (2) if the Administrator 
determines that the objection is of central relevance to the outcome of 
the rule. Therefore, reconsideration is not required if the objections 
by a petitioner were raised or could reasonably have been raised during 
the pendency of the rulemaking. Moreover, even in the circumstance 
where a particular objection could not have been raised earlier, 
reconsideration is not required if EPA determines that such objections 
would not have altered the outcome of the rule had they been raised 
earlier.
    TFI argues in its petition that EPA should reconsider the entire 
1992 rule revising subpart R because the 1989 notice convening the 
reconsideration proceeding did not specify, or provide an opportunity 
for comment on, the details of the technical methodology which EPA 
subsequently utilized in analyzing the risks associated with 
alternative uses of phosphogypsum. However, EPA does not believe that 
it was obligated to select and specify each of the technical models to 
be utilized in its analysis and to describe all of the analytic 
assumptions to be utilized before convening the reconsideration 
proceeding. TFI also argues in its petition that a number of the 
elements of the rule as it was promulgated were not specifically 
proposed for notice and comment. In general, EPA believes that the 
provisions of the rule adopted in 1992 were a logical outgrowth of the 
options described in the 1989 reconsideration notice and the comments 
received concerning those options.
    EPA acknowledges that TFI did not have sufficient information to 
state many of the detailed technical objections set forth in its 
petition for reconsideration within the period provided for public 
comment. However, under the criteria set forth in CAA section 
307(d)(7)(B), it is still necessary for EPA to assess the substantive 
significance of each of these objections to determine whether it is of 
central relevance to the outcome of the rule and therefore an 
appropriate basis for reconsideration.
    Applying the criteria for reconsideration set forth in section 
307(d)(7)(B) to the August 3, 1992 TFI petition, EPA has concluded that 
certain objections raised by TFI do warrant convening a reconsideration 
proceeding concerning particular provisions included in the 1992 
revisions to Subpart R, but that the remaining objections by TFI do not 
warrant reconsideration of the remaining provisions of the 1992 rule.

III. Decision to Partially Grant Petition

    In its petition, TFI objects that the EPA analysis of the potential 
risks associated with the use of phosphogypsum in research and 
development assumes an emanation rate for radon from phosphogypsum in 
the laboratory 40 times greater than the rate for phosphogypsum in 
stacks, and that EPA has therefore greatly overestimated the risk 
presented by the research and development use. TFI also argues that the 
analysis by EPA assumed that normal good laboratory practices, such as 
segregated storage of hazardous materials, limiting removal of 
materials to an as needed basis, appropriate ventilation, and 
appropriate disposal of used material, would be disregarded.
    The analysis by EPA of the potential risks associated with the 
research and development use assumed that all of the free radon 
generated by phosphogypsum containing 26pCi/g radium-226 would be 
released to a small laboratory room with a total volume of 64 cubic 
meters and an air volume of 50 cubic meters. The EPA analysis thus 
assumed that none of the radon would be retained in the physical matrix 
of the phosphogypsum long enough to permit further decay the radon and 
adsorption of the decay products, which would prevent release of 
gaseous radon to the laboratory environment. While there are certainly 
some experiments or circumstances where all of the radon generated by 
decay of radium in the phosphogypsum could be released in the 
laboratory, EPA has concluded that this would be unusual and that such 
high emanation rates would be infrequent.
    In addition, EPA discovered during its review of the analysis of 
potential risks associated with the research and development use that 
EPA assumed in its estimation of radon emissions to the laboratory 
environment that five 700 pound drums would be stored or utilized in 
the same area of the laboratory, rather than the single 700 pound drum 
permitted by the rule. As a consequence, the portion of the risk to 
laboratory personnel attributable to radon emissions was overestimated 
by a factor of five. In view of these conclusions, EPA has determined 
that the objections by TFI are of central relevance to the provision 
limiting use of phosphogypsum in research and development to no more 
than 700 pounds, and that EPA should request further comment on the 
assumptions to be utilized in analyzing the risks associated with the 
research and development use.
    In its petition, TFI also argues that it is not clear from the text 
of the 1992 rule whether more than one research and development 
activity utilizing 700 pounds of phosphogypsum would be permitted at a 
single facility, as well as whether or not a single research activity 
would be limited to a total of 700 pounds or only to 700 pounds at any 
given time. TFI states that it assumes that multiple research and 
development activities each utilizing 700 pounds of phosphogypsum would 
be permitted at a single facility, and that the 700 pound limit applies 
only to the amount of phosphogypsum on hand at any given time, but 
requests that EPA clarify the rule. EPA believes that TFI has correctly 
construed the rule and questions the need for further clarification of 
the existing rule. However, the fact that a given laboratory worker 
might be exposed to radiation as a result of more than one research and 
development activity utilizing phosphogypsum was not considered in the 
EPA risk analysis. Accordingly, EPA has decided that it will also 
request comment on whether there should be any limit on multiple 
research and development activities at a single facility or by a 
particular investigator, and how the possibility of greater exposures 
attributable to multiple research and development activities should be 
accounted for in the EPA analysis.
    In its petition, TFI objects that it is not clear what purpose is 
served by requiring owners or operators to conduct sampling or 
measurement of radium-226 in phosphogypsum distributed for use in 
research and development, because there is no quantitative limit on the 
amount of radium-226 which phosphogypsum distributed for this use may 
contain. Because there is no limit on the amount of radium permitted in 
phosphogypsum distributed for research and development use, EPA assumed 
in its analysis of potential risks associated with such use that the 
phosphogypsum would contain high levels of radium. EPA believes that in 
most instances analysis of the radium-226 content in phosphogypsum 
distributed for use in research and development will be necessary as 
part of the research activity. However, EPA has concluded that 
requiring certification documents accompanying phosphogypsum 
distributed for use in research and development to include quantitative 
analyses of radium content is not necessary to monitor compliance. 
Accordingly, EPA has decided that this objection by TFI is also of 
central relevance to the outcome of this provision.
    In view of the multiple objections by TFI which are of central 
relevance to the outcome of 40 CFR 61.205, the provision of the revised 
Subpart R governing distribution of phosphogypsum for use in research 
and development, EPA has decided to partially grant the TFI petition by 
convening a proceeding to reconsider 40 CFR 61.205. To implement this 
decision, EPA is preparing and will publish shortly a notice of 
reconsideration specifying the specific subjects on which further 
comment will be requested and the range of options to be considered.
    In its petition, TFI objects that the formula set forth in 40 CFR 
61.207(d), which is used to establish the number of samples necessary 
to determine a representative average radium-226 concentration, is 
ambiguous, because it does not specify the amount of allowable error. 
EPA agrees with this objection. The failure to include an allowable 
error component in the formula was an inadvertent omission. EPA 
believes that it would not be necessary to convene a reconsideration 
proceeding for the sole purpose of correcting this inadvertent 
omission, but has decided to include 40 CFR 61.207(d) among the 
provisions to be reconsidered. To assist affected facilities in 
complying with the existing rule while the reconsideration proceeding 
is pending, EPA will provide specific guidance in the notice of 
reconsideration concerning selection of an appropriate error component.

IV. Decision to Partially Deny Petition

    EPA has carefully reviewed all of the remaining objections set 
forth in the TFI petition for reconsideration. Based on that review, 
EPA has concluded that none of the remaining technical objections by 
TFI to the EPA analysis of the potential risks of phosphogypsum use are 
of central relevance to the outcome of the 1992 rule. In addition, EPA 
has determined that some of the remaining policy objections by TFI 
could have been raised during the public comment period, and that none 
of the remaining policy objections is of central relevance to the 
outcome of the rule.
    Based on its review of the remaining objections in the TFI petition 
for reconsideration, EPA is denying the TFI petition with respect to 
all provisions in the rule not specifically included in the decision to 
grant reconsideration set forth above. The Agency's response to each of 
the remaining TFI objections is summarized below.

A. Technical Objections

    Objection: The radon emanation coefficient of 0.3 for phosphogypsum 
is too high. Field observations (HP91) and the PATHRAE model (EPA87) 
suggest the radon emanation coefficient for phosphogypsum in soil 
should be 0.2. The coefficient used is 50 percent larger than suggested 
by empirical data, but no explanation is given for why the higher value 
was selected.
    Response: The selection of 0.3 for the radon emanation coefficient 
(E) is based on 30 measurements using phosphogypsum from four sites in 
central Florida and Texas (RO88). As this reference is not publicly 
available, it was not cited in the Background Information Document 
(BID). The measurements were made at typical in-situ moistures for 
phosphogypsum stacks. The arithmetic average of these data is about 
0.35. Thus, the value of 0.3 used in the BID is reasonable and 
applicable.
    The data and other information (NI82) show the dependence of E on 
moisture. At lower moisture levels E increases significantly with 
moisture. This is also demonstrated in the work of van Dijk and deJong 
(HP91) referenced by TFI. As their Figure 4 shows, E for phosphogypsum 
can increase by more than 50 percent as equilibrium moisture increases. 
The E values of 0.18 and 0.19, reported in their Table 2 and referenced 
by TFI, are for nearly their driest conditions. As they were interested 
in the effects of using phosphogypsum in building materials, these 
lower values were appropriate. However, the exalation rates that they 
measured at higher moistures give E values of about 0.28. This is 
consistent with the value of 0.30 used in the risk assessments. 
Moisture saturations in soils under residences are expected to be near 
the values in the Rogers measurements and closer to the higher moisture 
measurements by van Dijk and deJong.
    The higher emanation coefficients are further confirmed in field 
measurements of the specific radon flux from the surface of 
phosphogypsum stacks. In 1985, Dr. C.E. Roessler (University of 
Florida) determined that the specific radon flux from phosphogypsum 
stacks in central Florida was 1 pCi/m2-s per pCi/g of Ra-226 in 
the phosphogypsum. This value requires an E value of at least 0.29.
    TFI also commented that an E of 0.2 was used in the PATHRAE model 
(EPA87). This value was used in an example problem in the reference. 
However, the example problem was for soil, not phosphogypsum, and 
should not be construed as a recommendation for all cases.
    Objection: The radon diffusion for concrete is given as 16 m2/
y. Published measurements of radon diffusion in concrete (HP80a, HP83) 
provide values that are factors of 8 to 15 lower. Use of the lower 
radon diffusion coefficients would reduce the indoor radon risks by a 
factor of about two.
    Response: The value of 16 m2/y (5.1  x  10-3 cm2/s) 
for the radon diffusion coefficient of concrete (Dc) is the upper 
end of the range of Dc's measured for residential concretes by 
Nielson and Rogers (NI91). The upper end of the range was used because 
PATHRAE only considers radon diffusion as the entry mechanism for soil 
radon. While diffusion may dominate radon entry (TA90, RO90), advective 
transport is also a factor and may dominate under some circumstances 
(RO90, LO90). The value that was used for Dc in the risk 
assessments partially accounts for the radon entry by advection.
    TFI refers to Dc measurements made by Zapalac (HP83) and 
Stranden and Berteig (HP80a). Zapalac reports Dc values of 3.3  x  
10-4 cm2/s and 6.0  x  10-4 cm2/s for concretes 
with densities of 2.3 and 2.4 g/cm3. The measurements by Rogers 
and Nielson (RO90) also give the dependence of Dc on the concrete 
density. The residential concretes that they tested had densities 
generally of 2.1 g/cm3 or less. For the densities used by Zapalac, 
the Rogers and Nielson correlation predicts Dc values of 1.2  x  
10-4 and 4.0  x  10-4 cm2/s. Thus, the data used in the 
risk assessments are consistent with Zapalac's data.
    Stranden and Berteig did not give the densities for their concrete, 
so a direct comparison is not possible. However, it is worth noting 
that since the Stranden and Berteig measurements relied only on the 
radon generated within the concrete, they are not a very sensitive 
measure of Dc. Since a significant fraction of residential 
concretes have densities less than 2.2 g/cm3, the value of 5.1  x  
10-3 cm2/s for Dc is reasonable for the risk 
assessments.
    Objection: The radon decay product equilibrium fraction of 0.5 is 
the upper bound of the range of 0.3 to 0.5 found in the Florida 
Statewide Radiation Study. The average indoor radon equilibrium 
fraction from houses where the radon concentrations ranged from 0.4 to 
>8 pCi/l was 0.42. The National Council on Radiation Protection and 
Measurements (NCRP) in its Report 94 and the United Nations Scientific 
Committee on the Effects of Atomic Radiation (UNSCEAR) recommend 0.4 as 
an indoor equilibrium fraction. The selected value of 0.5 is also 
inconsistent with the assumption of 2 air changes per hour. Krisiuk 
(HP80b) gives a value of 0.36 for a ventilation rate of 2 air changes 
per hour. If other removal mechanisms are considered (e.g., plateout 
and deposition), the equilibrium would be even lower. Use of 0.5 for 
the equilibrium fraction results in overestimating the risks from 
indoor radon exposure by a factor of at least 1.4.
    Response: The EPA's radon risk factor incorporates a 0.5 
equilibrium fraction. The value of 2 air changes per hour was not 
chosen to be consistent with the radon decay product equilibrium 
fraction. If they were made consistent, then 1 air change per hour 
(HP80b) would have been used. The value of 1 air change per hour is 
about the average for residences in the United States (NA88), and 
results in an average equilibrium fraction of about 0.5. Thus, the use 
of 2 air changes per hour in the risk assessments is non-conservative.
    Objection: Based on estimates of the NCRP in Report No. 45, the 
PATHRAE model overestimates the effective gamma dose rate by a factor 
of 2.5.
    Response: For Scenarios 1 and 2, the BID gives an annual external 
gamma dose equivalent of 3.5 mrem/y from a soil Ra-226 concentration of 
0.69 pCi/g. This is equal to a dose rate of 2.5 urad/h per Pci/g of Ra-
226. TFI references the 1.6 urad/hr per pCi/g value recommended by the 
NCRP (NCRP75 and NCRP87). Thus, the NCRP's value is lower than the 
PATHRAE results by 36 percent, not the factor of 2.5 claimed by TFI.
    The external gamma dose rate at a given distance above soil 
containing Ra-226 depends on the source geometry and the self-
absorption of the radiation in the soil. For the conditions being 
assessed, an infinite plane best describes source geometry and the 
PATHRAE model used an infinite plane dose factor for Ra-226 and its 
decay products of 1.67  x  10-4 mrem/y per pCi/m2. As this 
value is nearly the same as the value of 1.69  x  10-4 mrem/y per 
pCi/m2 used by the DOE (DOE88), it does not appear to be too high. 
The effect of self-absorption is quite variable and depends on the soil 
density and the low gamma energy cutoff value. The NCRP's theoretical 
value is based on work by Beck (BE75), which assumes a soil density of 
1.6 g/cm3 and used 50 KeV as the low energy cutoff values. These 
differences, particularly the difference in the low energy cutoff 
values, account for the differences between the BID and the results 
that would be obtained using the NCRP's value of 1.6 urad/hr per pCi/g. 
It should also be noted that both values (1.6 urad/hr per pCi/g and 2.5 
urad/hr per pCi/g) are within the variability of field measurements.
    Objection: The use of a 70 year exposure period for residential 
scenarios is inconsistent with the Superfund policy of using 90th 
percentile estimates. The 90th percentile value is 30 years.
    Response: The BID generally reports lifetime risk per year of 
exposure. However, in Scenario 7, the risks for a lifetime of exposure 
are presented by multiplying the risk per year of exposure by 70 years. 
This is consistent with the EPA's policy under the Clean Air Act which 
was explained in the preamble to the 1989 National Emission Standards 
for Radon Emissions from Phosphogypsum Stacks (54 FR 51661) and which 
has been used in these rulemaking proceedings.
    However, as explained in the preamble, the difference that would be 
caused by assuming a shorter period of exposure is not very 
significant. For an assumed constant rate of exposure, people receive 
over 60% of their total lifetime risk during their first nineteen 
years. To change the period of exposure from 70 years to the first 19 
years of life would change the final results by less than a factor of 
two.
    Objection: Radioactive decay during the 70-year residential 
exposure period is neglected.
    Response: Neglecting radioactive decay during the 70-year 
residential exposure period introduces a negligible conservatism to the 
results. Accounting for radioactive decay would have reduced the 
estimated risks by about 1.5 percent.
    Objection: The BID fails to account for removal of soil during home 
construction at former phosphogypsum use sites.
    Response: Some home construction may involve the removal of the 
contaminated soil. However, it is more likely that the homes would have 
the contaminated soil under or adjacent to them. Since the analysis 
focused on the potential risks to the most exposed members of the 
population, assuming that the contamination remains under and adjacent 
to any homes that are built is reasonable.
    Objection: The derivation of the presumptively safe level of 10 
pCi/g Ra-226 for phosphogypsum used in agriculture is based on the 95th 
percentile application rate of 2,700 lb/acre for 100 years. Using the 
90th percentile rate, per Superfund policy, would be more appropriate. 
More importantly, the application rate of 2,700 lb/acre is for soil 
reclamation rather than soil productivity. Soil reclamation would not 
require applications at this rate over a 100-year period. By combining 
the application rate for soil reclamation with the frequency rate for 
soil productivity the EPA has greatly overestimated the total 
phosphogypsum application that would occur over the 100-year period.
    Response: Superfund guidance is not necessarily applicable under 
this NESHAP. However, TFI has not correctly stated the Superfund 
guidance. That guidance for calculating reasonable maximum exposure 
calls for the choice of 95th percentile values where available, or 90th 
percentile values where 95th percentile values are not available.
    The 95th percentile application rate for phosphogypsum used in 
agriculture was calculated from data reported by TFI, based on a 
questionnaire they sent to users of phosphogypsum (Docket A-79-11, XV-
D-100A, appendix, Tab 38). The 95th percentile was based on considering 
application rates for a variety of crops produced in California and for 
peanut production in the South, based on the assumption that 
agricultural usage of phosphogypsum is about equally split between the 
California and the remainder of the U.S. Although the data from 
California show much higher application rates than those for peanuts, 
we do not believe that California's rates are necessarily associated 
with reclamation. Phosphogypsum is used for land reclamation in 
California; however, an expert on the use of phosphogypsum in 
California estimates that the application rate for reclamation is about 
10,000 pounds per acre, considerably higher that the rates reported in 
the TFI questionnaire. He also estimates that the application rate for 
production is approximately equal to the rates reported in the TFI 
questionnaire (Docket A-79-11, XVII-B-41).
    Objection: The assessment of agricultural use does not consider the 
differing application rates in different geographic areas of the 
country.
    Response: The risk analysis in the BID gives risks for various 
application rates. Use of the 95th percentile application rate to 
select a single value for the maximum permissible radium-226 content in 
phosphogypsum distributed for agricultural use greatly simplifies 
compliance and enforcement procedures.
    Objection: The method prescribed for determining Ra-226 
concentrations is for airborne effluents, not solids.
    Response: The rule references Method 114 in appendix B of part 61. 
Method 114 provides requirements for: (1) Stack sampling of effluents; 
(2) radiochemical methods for determining the quantity of radionuclides 
in a sample; and (3) quality assurance methods. Clearly, the portions 
of Method 114 that relate to the collection of the effluent sample are 
not applicable to determining the Ra-226 content of phosphogypsum 
removed from a stack. However, the portions of Method 114 that relate 
to radiochemical methods of determining the quantity of Ra-226 present 
in the phosphogypsum (i.e., ``the principles of measurement'') and the 
specified quality assurance methods are valid regardless of how the 
sample was obtained.

B. Policy Objections

    Objection: The EPA analysis of potential risks and the EPA decision 
criteria with respect to the use of phosphogypsum in road construction 
are absurd, because even naturally occurring materials would not meet 
the EPA standard for a presumptively safe level of exposure to 
radioactivity.
    Response: It is well known that naturally occurring radium-226 
levels in soil can release amounts of radon which are potentially 
hazardous to occupants of structures built on such soil. Phosphogypsum 
can contain radium-226 levels far in excess of the amount of activity 
naturally present in soil. It is not absurd for EPA to take actions to 
control the additional risks associated with the higher activity levels 
in phosphogypsum simply because naturally occurring construction 
materials may also present a risk in some circumstances.
    Objection: The requirement that a person generating phosphogypsum 
must first place it in a stack, and then measure and certify the radium 
activity in the stack, before removing phosphogypsum from the stack and 
distributing it for alternative use is cumbersome and unnecessary. 
Instead, if phosphogypsum is designated for reuse, segregated, and 
routed to a distribution holding point, the radium-226 content of the 
phosphogypsum can be measured at either the segregation or the 
distribution point.
    Response: The provisions permitting distribution of phosphogypsum 
for alternative uses are specific exceptions to the work practice 
requirements which require persons generating phosphogypsum to dispose 
of the material in a stack and to manage the stack in a specified 
manner. For the provisions in the rule to operate properly, the 
generator of phosphogypsum must determine that a given quantity of 
phosphogypsum conforms to all of the requirements for distribution for 
alternative uses before such distribution occurs. To the extent that 
TFI is suggesting that persons other than those who generated the 
phosphogypsum in the first instance should be permitted to measure the 
radium-226 activity levels after distribution of the phosphogypsum has 
already occurred, this cannot be reconciled with the Agency's objective 
to assure safe disposal in managed and monitored stacks of all 
phosphogypsum which does not meet the threshold requirements for 
distribution for alternative uses.
    EPA notes that 40 CFR 61.201(c) defines any pile of phosphogypsum 
waste as a phosphogypsum stack. If the person who generates the 
phosphogypsum in the first instance wishes to segregate phosphogypsum 
designated for alternative use in a separate stack and measure the 
activity levels in that stack separately, the rule permits this 
approach. However, any materials in any additional stack which are not 
lawfully distributed for an alternative use must be managed by the 
owner or operator in the manner specified by the rule.
    Objection: The limitation to 700 pounds of phosphogypsum for each 
specific research and development activity necessarily means that 
research and development in the field will be impossible.
    Response: EPA notes that it has decided to reconsider the 700 pound 
limitation. However, 40 CFR 61.205 was designed to permit research and 
development activities involving phosphogypsum to proceed in the 
laboratory, not to authorize large scale field research. Proposals to 
conduct field studies utilizing phosphogypsum should instead be 
submitted for prior EPA approval pursuant to 40 CFR 61.206.
    Objection: The procedures for certification in 40 CFR 61.208 are 
overly burdensome and unnecessary. They require a multi-party paperwork 
trail for materials that are presumptively safe. EPA should just 
require the person who generates phosphogypsum to certify at the end of 
the year that all of its shipments met applicable legal requirements.
    Response: EPA believes that the procedures requiring distributors, 
retailers, or resellers to prepare certification documents and to 
retain copies of certification documents provided by the person from 
whom the phosphogypsum was obtained are necessary to adequately monitor 
compliance with the requirements in the rule. Without such 
documentation, it would be much more difficult or even impossible to 
investigate and take appropriate enforcement action if non-conforming 
phosphogypsum is found to have been distributed or sold for an 
alternative use. EPA notes that farmers or agricultural end-users who 
purchase phosphogypsum for an agricultural use are not required to 
prepare or maintain records, but that distributors who sell 
phosphogypsum for an agricultural use must do so.
    Objection: Risks associated with phosphogypsum use should be 
controlled by state and local governments through restrictions on 
building construction rather than by EPA.
    Response: EPA hopes that state and local governments will adopt 
appropriate measures to control hazards associated with radon emissions 
at building sites. However, EPA does not believe that it is appropriate 
for EPA to sanction specific activities which unduly increase the 
radium content of the land and the risks associated with building 
construction, based on an assumption that state or local building codes 
will mitigate the resultant problem.

V. Judicial Review

    The decision by EPA to partially deny the August 3, 1992 TFI 
petition for reconsideration is final agency action based on a 
determination of nationwide scope or effect. TFI may seek review of the 
decision by EPA to partially deny its petition in the United States 
Court of Appeals for the District of Columbia Circuit within 60 days 
from the date this notice is published in the Federal Register. EPA 
notes that TFI has previously agreed that, if TFI seeks judicial review 
of the decision by EPA to partially deny its petition for 
reconsideration, TFI will move to consolidate such review with the 
review of the 1992 rule which is currently pending in The Fertilizer 
Institute v. Environmental Protection Agency, No. 92-1320 (DC Cir.) and 
ManaSota-88 v. Browner, No. 92-1330 (DC Cir.).
    The decision by EPA to partially grant the TFI petition does not 
constitute final agency action and is therefore not presently subject 
to judicial review. After EPA takes final action in the resulting 
reconsideration proceeding, any person who participated in that 
proceeding may seek judicial review of such action.

VI. References

BE75  Beck, H.L., ``The Physics of Environmental Gamma Radiation 
Fields,'' Proceedings, Natural Radiation in the Environment II, 
1975.
DOE88  U.S. Department of Energy, External Dose-Rate Conversion 
Factors for Calculation of Dose to the Public, DOE/EH-0070, 1988.
EPA87 U.S. Environmental Protection Agency, Low-Level and NARM 
Radioactive Wastes Model--PATHRAE-EPA Methodology and Users Manual, 
EPA 520/1-87-028, 1987.
HP80a Stranden, E. and Berteig, L., ``Radon in Dwellings and 
Influencing Factors,'' Health Physics 30:275, 1980.
HP80b Krisiuk, E.M., ``Airborne Radioactivity in Buildings,'' Health 
Physics 38:199, 1980.
HP83 Zapalac, G.H., ``A Time-Dependent Method for Characterizing the 
Diffusion of 222Rn in Concrete,'' Health Physics 45:377, 1983.
HP91 van Dijk, W. and deJong, P., ``Determining the 222Rn 
Exhalation Rate of Building Materials Using Liquid Scintillation 
Counting,'' Health Physics 61:501, 1991.
LO90 Loureiro, C.O., et al., ``Three-Dimensional Simulation of Radon 
Transport into Houses with Basements Under Constant Negative 
Pressure,'' Environmental Science and Technology 24:1338, 1990.
NA88 Nazaroff, W.W. and Nero, A.V., Radon and Its Decay Products in 
Indoor Air, pp. 131-157, John Wiley & Sons, New York, 1988.
NCRP75 National Council on Radiation Protection and Measurements, 
Natural Background Radiation in the United States, NCRP Report No. 
45, 1975.
NCRP87 National Council on Radiation Protection and Measurements, 
Exposure of the Population in the United States and Canada from 
Natural Background Radiation, NCRP Report No. 94, 1987.
NI82 Nielson, K.K., ``Radon Emanation Characteristics of Uranium 
Mill Tailings,'' Proceedings of the Fifth Symposium on Mill Tailings 
Management, pp. 355-567, Colorado State University Press, 1982.
NI91 Nielson, K.K., and Rogers, V.C., ``Radon Entry into Dwellings 
Through Concrete Floors,'' Proceedings of the 1991 International 
Symposium on Radon and Radon reduction Technology, Philadelphia, PA, 
EPA-600/9-91-37c, 1991.
RO88 Rogers, V.C., Characterization of the Former Borden Property in 
Texas City, Texas, Rogers and Associates Engineering Corp., RAE 
8602/1-2, 1987.
RO90 Rogers, V.C. and Nielson, K.K., ``Benchmark and Application of 
the RAETRAD Model,'' Proceedings of the 1990 International Symposium 
on Radon and Radon Reduction Technology, Atlanta, GA, EPA/600/9-90/
005c, 1990.
TA90 Tanner, A.B., ``The role of Diffusion in Radon Entry in 
Houses,'' Proceedings of the 1990 International Symposium on Radon 
and Radon Reduction Technology, Atlanta, GA, EPA/600/9-90/005c, 
1990.

    Dated: March 7, 1994.
Carol M. Browner,
Administrator.
[FR Doc. 94-5993 Filed 3-23-94; 8:45 am]
BILLING CODE 6560-50-P