[Title 40 CFR DD]
[Code of Federal Regulations (annual edition) - July 1, 1996 Edition]
[Title 40 - PROTECTION OF ENVIRONMENT]
[Chapter I - ENVIRONMENTAL PROTECTION]
[Subchapter I - SOLID WASTES (Continued)]
[Part 265 - INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES]
[Subpart Dd - Containment Buildings]
[From the U.S. Government Publishing Office]




  40
  PROTECTION OF ENVIRONMENT
  13
  1996-07-01
  1996-07-01
  false
  Containment Buildings
  DD
  Subpart DD
  
    PROTECTION OF ENVIRONMENT
    ENVIRONMENTAL PROTECTION
    SOLID WASTES (Continued)
    INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES
  


                    Subpart DD--Containment Buildings

    Source: 57 FR 37268, Aug. 18, 1992, unless otherwise noted.



Sec. 265.1100  Applicability.

    The requirements of this subpart apply to owners or operators who 
store or treat hazardous waste in units designed and operated under 
Sec. 265.1101 of this subpart. These provisions will become effective on 
February 18, 1993, although the owner or operator may notify the 
Regional Administrator of his intent to be bound by this subpart at an 
earlier time. The owner or operator is not subject to the definition of 
land disposal in RCRA section 3004(k) provided that the unit:
    (a) Is a completely enclosed, self-supporting structure that is 
designed and constructed of manmade materials of sufficient strength and 
thickness to support themselves, the waste contents, and any personnel 
and heavy equipment that operate within the units, and to prevent 
failure due to pressure gradients, settlement, compression, or uplift, 
physical contact with the hazardous wastes to which

[[Page 498]]

they are exposed; climatic conditions; and the stresses of daily 
operation, including the movement of heavy equipment within the unit and 
contact of such equipment with containment walls;
    (b) Has a primary barrier that is designed to be sufficiently 
durable to withstand the movement of personnel and handling equipment 
within the unit;
    (c) If the unit is used to manage liquids, has:
    (1) A primary barrier designed and constructed of materials to 
prevent migration of hazardous constituents into the barrier;
    (2) A liquid collection system designed and constructed of materials 
to minimize the accumulation of liquid on the primary barrier; and
    (3) A secondary containment system designed and constructed of 
materials to prevent migration of hazardous constituents into the 
barrier, with a leak detection and liquid collection system capable of 
detecting, collecting, and removing leaks of hazardous constituents at 
the earliest possible time, unless the unit has been granted a variance 
from the secondary containment system requirements under 
Sec. 265.1101(b)(4);
    (d) Has controls as needed to permit fugitive dust emissions; and
    (e) Is designed and operated to ensure containment and prevent the 
tracking of materials from the unit by personnel or equipment.



Sec. 265.1101  Design and operating standards.

    (a) All containment buildings must comply with the following design 
standards:
    (1) The containment building must be completely enclosed with a 
floor, walls, and a roof to prevent exposure to the elements, (e.g., 
precipitation, wind, run-on), and to assure containment of managed 
wastes.
    (2) The floor and containment walls of the unit, including the 
secondary containment system if required under paragraph (b) of this 
section, must be designed and constructed of materials of sufficient 
strength and thickness to support themselves, the waste contents, and 
any personnel and heavy equipment that operate within the unit, and to 
prevent failure due to pressure gradients, settlement, compression, or 
uplift, physical contact with the hazardous wastes to which they are 
exposed; climatic conditions; and the stresses of daily operation, 
including the movement of heavy equipment within the unit and contact of 
such equipment with containment walls. The unit must be designed so that 
it has sufficient structural strength to prevent collapse or other 
failure. All surfaces to be in contact with hazardous wastes must be 
chemically compatible with those wastes. EPA will consider standards 
established by professional organizations generally recognized by the 
industry such as the American Concrete Institute (ACI) and the American 
Society of Testing Materials (ASTM) in judging the structural integrity 
requirements of this paragraph. If appropriate to the nature of the 
waste management operation to take place in the unit, an exception to 
the structural strength requirement may be made for light-weight doors 
and windows that meet these criteria:
    (i) They provide an effective barrier against fugitive dust 
emissions under paragraph (c)(1)(iv); and
    (ii) The unit is designed and operated in a fashion that assures 
that wastes will not actually come in contact with these openings.
    (3) Incompatible hazardous wastes or treatment reagents must not be 
placed in the unit or its secondary containment system if they could 
cause the unit or secondary containment system to leak, corrode, or 
otherwise fail.
    (4) A containment building must have a primary barrier designed to 
withstand the movement of personnel, waste, and handling equipment in 
the unit during the operating life of the unit and appropriate for the 
physical and chemical characteristics of the waste to be managed.
    (b) For a containment building used to manage hazardous wastes 
containing free liquids or treated with free liquids (the presence of 
which is determined by the paint filter test, a visual examination, or 
other appropriate means), the owner or operator must include:
    (1) A primary barrier designed and constructed of materials to 
prevent the

[[Page 499]]

migration of hazardous constituents into the barrier (e.g. a geomembrane 
covered by a concrete wear surface).
    (2) A liquid collection and removal system to prevent the 
accumulation of liquid on the primary barrier of the containment 
building:
    (i) The primary barrier must be sloped to drain liquids to the 
associated collection system; and
    (ii) Liquids and waste must be collected and removed to minimize 
hydraulic head on the containment system at the earliest practicable 
time that protects human health and the environment.
    (3) A secondary containment system including a secondary barrier 
designed and constructed to prevent migration of hazardous constituents 
into the barrier, and a leak detection system that is capable of 
detecting failure of the primary barrier and collecting accumulated 
hazardous wastes and liquids at the earliest practicable time.
    (i) The requirements of the leak detection component of the 
secondary containment system are satisfied by installation of a system 
that is, at a minimum:
    (A) Constructed with a bottom slope of 1 percent or more; and
    (B) Constructed of a granular drainage material with a hydraulic 
conductivity of 1  x  10-\2\ cm/sec or more and a thickness of 12 
inches (30.5 cm) or more, or constructed of synthetic or geonet drainage 
materials with a trasmissivity of 3  x  10-\5\ m \2\/sec or more.
    (ii) If treatment is to be conducted in the building, an area in 
which such treatment will be conducted must be designed to prevent the 
release of liquids, wet materials, or liquid aerosols to other portions 
of the building.
    (iii) The secondary containment system must be constructed of 
materials that are chemically resistant to the waste and liquids managed 
in the containment building and of sufficient strength and thickness to 
prevent collapse under the pressure exerted by overlaying materials and 
by any equipment used in the containment building. (Containment 
buildings can serve as secondary containment systems for tanks placed 
within the building under certain conditions. A containment building can 
serve as an external liner system for a tank, provided it meets the 
requirements of Sec. 265.193(d)(1). In addition, the containment 
building must meet the requirements of Sec. 265.193 (b) and (c) to be 
considered an acceptable secondary containment system for a tank.)
    (4) For existing units other than 90-day generator units, the 
Regional Administrator may delay the secondary containment requirement 
for up to two years, based on a demonstration by the owner or operator 
that the unit substantially meets the standards of this Subpart. In 
making this demonstration, the owner or operator must:
    (i) Provide written notice to the Regional Administrator of their 
request by February 18, 1993. This notification must describe the unit 
and its operating practices with specific reference to the performance 
of existing containment systems, and specific plans for retrofitting the 
unit with secondary containment;
    (ii) Respond to any comments from the Regional Administrator on 
these plans within 30 days; and
    (iii) Fulfill the terms of the revised plans, if such plans are 
approved by the Regional Administrator.
    (c) Owners or operators of all containment buildings must:
    (1) Use controls and practices to ensure containment of the 
hazardous waste within the unit; and, at a minimum:
    (i) Maintain the primary barrier to be free of significant cracks, 
gaps, corrosion, or other deterioration that could cause hazardous waste 
to be released from the primary barrier;
    (ii) Maintain the level of the stored/treated hazardous waste within 
the containment walls of the unit so that the height of any containment 
wall is not exceeded;
    (iii) Take measures to prevent the tracking of hazardous waste out 
of the unit by personnel or by equipment used in handling the waste. An 
area must be designated to decontaminate equipment and any rinsate must 
be collected and properly managed; and
    (iv) Take measures to control fugitive dust emissions such that any 
openings (doors, windows, vents, cracks, etc.) exhibit no visible 
emissions. In

[[Page 500]]

addition, all associated particulate collection devices (e.g., fabric 
filter, electrostatic precipitator) must be operated and maintained with 
sound air pollution control practices. This state of no visible 
emissions must be maintained effectively at all times during normal 
operating conditions, including when vehicles and personnel are entering 
and exiting the unit.
    (2) Obtain certification by a qualified registered professional 
engineer that the containment building design meets the requirements of 
paragraphs (a) through (c) of this section. For units placed into 
operation prior to February 18, 1993, this certification must be placed 
in the facility's operating record (on-site files for generators who are 
not formally required to have operating records) no later than 60 days 
after the date of initial operation of the unit. After February 18, 
1993, PE certification will be required prior to operation of the unit.
    (3) Throughout the active life of the containment building, if the 
owner or operator detects a condition that could lead to or has caused a 
release of hazardous waste, must repair the condition promptly, in 
accordance with the following procedures.
    (i) Upon detection of a condition that has led to a release of 
hazardous waste (e.g., upon detection of leakage from the primary 
barrier) the owner or operator must:
    (A) Enter a record of the discovery in the facility operating 
record;
    (B) Immediately remove the portion of the containment building 
affected by the condition from service;
    (C) Determine what steps must be taken to repair the containment 
building, remove any leakage from the secondary collection system, and 
establish a schedule for accomplishing the cleanup and repairs; and
    (D) Within 7 days after the discovery of the condition, notify the 
Regional Administrator of the condition, and within 14 working days, 
provide a written notice to the Regional Administrator with a 
description of the steps taken to repair the containment building, and 
the schedule for accomplishing the work.
    (ii) The Regional Administrator will review the information 
submitted, make a determination regarding whether the containment 
building must be removed from service completely or partially until 
repairs and cleanup are complete, and notify the owner or operator of 
the determination and the underlying rationale in writing.
    (iii) Upon completing all repairs and cleanup the owner or operator 
must notify the Regional Administrator in writing and provide a 
verification, signed by a qualified, registered professional engineer, 
that the repairs and cleanup have been completed according to the 
written plan submitted in accordance with paragraph (c)(3)(i)(D) of this 
section.
    (4) Inspect and record in the facility's operating record, at least 
once every seven days, data gathered from monitoring equipment and leak 
detection equipment as well as the containment building and the area 
immediately surrounding the containment building to detect signs of 
releases of hazardous waste.
    (d) For containment building that contains both areas with and 
without secondary containment, the owner or operator must:
    (1) Design and operate each area in accordance with the requirements 
enumerated in paragraphs (a) through (c) of this section;
    (2) Take measures to prevent the release of liquids or wet materials 
into areas without secondary containment; and
    (3) Maintain in the facility's operating log a written description 
of the operating procedures used to maintain the integrity of areas 
without secondary containment.
    (e) Notwithstanding any other provision of this subpart, the 
Regional Administrator may waive requirements for secondary containment 
for a permitted containment building where the owner or operator 
demonstrates that the only free liquids in the unit are limited amounts 
of dust suppression liquids required to meet occupational health and 
safety requirements, and where containment of managed wastes and liquids 
can be assured without a secondary containment system.

[[Page 501]]



Sec. 265.1102  Closure and post-closure care.

    (a) At closure of a containment building, the owner or operator must 
remove or decontaminate all waste residues, contaminated containment 
system components (liners, etc.), contaminated subsoils, and structures 
and equipment contaminated with waste and leachate, and manage them as 
hazardous waste unless Sec. 261.3(d) of this chapter applies. The 
closure plan, closure activities, cost estimates for closure, and 
financial responsibility for containment buildings must meet all of the 
requirements specified in subparts G and H of this part.
    (b) If, after removing or decontaminating all residues and making 
all reasonable efforts to effect removal or decontamination of 
contaminated components, subsoils, structures, and equipment as required 
in paragraph (a) of this section, the owner or operator finds that not 
all contaminated subsoils can be practicably removed or decontaminated, 
he must close the facility and perform post-closure care in accordance 
with the closure and post-closure requirements that apply to landfills 
(Sec. 265.310). In addition, for the purposes of closure, post-closure, 
and financial responsibility, such a containment building is then 
considered to be a landfill, and the owner or operator must meet all of 
the requirements for landfills specified in subparts G and H of this 
part.
Secs. 265.1103--265.1110  [Reserved]

                         Appendices to Part 265

           Appendix I to Part 265--Recordkeeping Instructions

    The recordkeeping provisions of Sec. 265.73 specify that an owner or 
operator must keep a written operating record at his facility. This 
appendix provides additional instructions for keeping portions  of the 
operating record. See Sec. 265.73(b) for additional recordkeeping 
requirements.
    The following information must be recorded, as it becomes available, 
and maintained in the operating record until closure of the facility in 
the following manner:
    Records of each hazardous waste received, treated, stored, or 
disposed of at the facility which include the following:
    (1) A description by its common name and the EPA Hazardous Waste 
Number(s) from part 261 of this chapter which apply to the waste. The 
waste description also must include the waste's physical form, i.e., 
liquid, sludge, solid, or contained gas. If the waste is not listed in 
part 261, subpart D, of this chapter, the description also must include 
the process that produced it (for example, solid filter cake from 
production of ______, EPA Hazardous Waste Number W051).
    Each hazardous waste listed in part 261, subpart D, of this chapter, 
and each hazardous waste characteristic defined in part 261, subpart C, 
of this chapter, has a four-digit EPA Hazardous Waste Number assigned to 
it. This number must be used for recordkeeping and reporting purposes. 
Where a hazardous waste contains more than one listed hazardous waste, 
or where more than one hazardous waste characteristic applies to the 
waste, the waste description must include all applicable EPA Hazardous 
Waste Numbers.
    (2) The estimated or manifest-reported weight, or volume and 
density, where applicable, in one of the units of measure specified in 
Table 1; and

                                 Table 1                                
------------------------------------------------------------------------
              Unit of measure                          Code \1\         
------------------------------------------------------------------------
Gallons....................................  G                          
Gallons per Hour...........................  E                          
Gallons per Day............................  U                          
Liters.....................................  L                          
Liters Per Hour............................  H                          
Liters Per Day.............................  V                          
Short Tons Per Hour........................  D                          
Metric Tons Per Hour.......................  W                          
Short Tons Per Day.........................  N                          
Metric Tons Per Day........................  S                          
Pounds Per Hour............................  J                          
Kilograms Per Hour.........................  R                          
Cubic Yards................................  Y                          
Cubic Meters...............................  C                          
Acres......................................  B                          
Acre-feet..................................  A                          
Hectares...................................  Q                          
Hectare-meter..............................  F                          
Btu's per Hour.............................  I                          
------------------------------------------------------------------------
\1\ Single digit symbols are used here for data processing purposes.    

    (3) The method(s) (by handling code(s) as specified in Table 2) and 
date(s) of treatment, storage, or disposal.

Table 2.--Handling Codes for Treatment, Storage and Disposal Methods

    Enter the handling code(s) listed below that most closely represents 
the technique(s) used at the facility to treat, store or dispose of each 
quantity of hazardous waste received.

                               1. Storage

S01  Container (barrel, drum, etc.)
S02  Tank
S03  Waste Pile
S04  Surface Impoundment

[[Page 502]]

S05  Drip Pad
S06  Containment Building (Storage)
S99  Other Storage (specify)

                              2. Treatment

(a)  Thermal Treatment--

T06  Liquid injection incinerator
T07  Rotary kiln incinerator
T08  Fluidized bed incinerator
T09  Multiple hearth incinerator
T10  Infrared furnace incinerator
T11  Molten salt destructor
T12  Pyrolysis
T13  Wet Air oxidation
T14  Calcination
T15  Microwave discharge
T18  Other (specify)

(b)  Chemical Treatment--

T19  Absorption mound
T20  Absorption field
T21  Chemical fixation
T22  Chemical oxidation
T23  Chemical precipitation
T24  Chemical reduction
T25  Chlorination
T26  Chlorinolysis
T27  Cyanide destruction
T28  Degradation
T29  Detoxification
T30  Ion exchange
T31  Neutralization
T32  Ozonation
T33  Photolysis
T34  Other (specify)

(c)  Physical Treatment--

    (1) Separation of components

T35  Centrifugation
T36  Clarification
T37  Coagulation
T38  Decanting
T39  Encapsulation
T40  Filtration
T41  Flocculation
T42  Flotation
T43  Foaming
T44  Sedimentation
T45  Thickening
T46  Ultrafiltration
T47  Other (specify)

    (2) Removal of Specific Components

T48  Absorption-molecular sieve
T49  Activated carbon
T50  Blending
T51  Catalysis
T52  Crystallization
T53  Dialysis
T54  Distillation
T55  Electrodialysis
T56  Electrolysis
T57  Evaporation
T58  High gradient magnetic separation
T59  Leaching
T60  Liquid ion exchange
T61  Liquid-liquid extraction
T62  Reverse osmosis
T63  Solvent recovery
T64  Stripping
T65  Sand filter
T66  Other (specify)

    (d)  Biological Treatment

T67  Activated sludge
T68  Aerobic lagoon
T69  Aerobic tank
T70  Anaerobic tank
T71  Composting
T72  Septic tank
T73  Spray irrigation
T74  Thickening filter
T75  Tricking filter
T76  Waste stabilization pond
T77  Other (specify)
T78  [Reserved]
T79  [Reserved]

    (e)  Boilers and Industrial Furnaces

T80  Boiler
T81  Cement Kiln
T82  Lime Kiln
T83  Aggregate Kiln
T84  Phosphate Kiln
T85  Coke Oven
T86  Blast Furnace
T87  Smelting, Melting, or Refining Furnace
T88  Titanium Dioxide Chloride Process Oxidation Reactor
T89  Methane Reforming Furnace
T90  Pulping Liquor Recovery Furnace
T91  Combustion Device Used in the Recovery of Sulfur Values From Spent 
          Sulfuric Acid
T92  Halogen Acid Furnaces
T93  Other Industrial Furnaces Listed in 40 CFR 260.10 (specify)

(f)  Other Treatment

T94  Containment Building (Treatment)

                               3. Disposal

D79  Underground Injection
D80  Landfill
D81  Land Treatment
D82  Ocean Disposal
D83  Surface Impoundment (to be closed as a landfill)
D99  Other Disposal (specify)

                      4. Miscellaneous (Subpart X)

X01  Open Burning/Open Detonation
X02  Mechanical Processing
X03  Thermal Unit
X04  Geologic Repository
X99  Other Subpart X (specify)

[45 FR 33232, May 19, 1980, as amended at 59 FR 13892, Mar. 24, 1994]

[[Page 503]]

                   Appendix II to Part 265--[Reserved]

 Appendix III to Part 265--EPA Interim Primary Drinking Water Standards

------------------------------------------------------------------------
                Parameter                       Maximum level (mg/l)    
------------------------------------------------------------------------
Arsenic..................................  0.05                         
Barium...................................  1.0                          
Cadmium..................................  0.01                         
Chromium.................................  0.05                         
Fluoride.................................  1.4-2.4                      
Lead.....................................  0.05                         
Mercury..................................  0.002                        
Nitrate (as N)...........................  10                           
Selenium.................................  0.01                         
Silver...................................  0.05                         
Endrin...................................  0.0002                       
Lindane..................................  0.004                        
Methoxychlor.............................  0.1                          
Toxaphene................................  0.005                        
2,4-D....................................  0.1                          
2,4,5-TP Silver..........................  0.01                         
Radium...................................  5 pCi/1                      
Gross Alpha..............................  15 pCi/1                     
Gross Beta...............................  4 millirem/yr                
Turbidity................................  1/TU                         
Coliform Bacteria........................  1/100 ml                     
------------------------------------------------------------------------
[Comment: Turbidity is applicable only to surface water supplies.]      

             Appendix IV to Part 265--Tests for Significance

    As required in Sec. 265.93(b) the owner or operator must use the 
Student's t-test to determine statistically significant changes in the 
concentration or value of an indicator parameter in periodic ground-
water samples when compared to the initial background concentration or 
value of that indicator parameter. The comparison must consider 
individually each of the wells in the monitoring system. For three of 
the indicator parameters (specific conductance, total organic carbon, 
and total organic halogen) a single-tailed Student's t-test must be used 
to test at the 0.01 level of significance for significant increases over 
background. The difference test for pH must be a two-tailed Student's t-
test at the overall 0.01 level of significance.
    The student's t-test involves calculation of the value of a t-
statistic for each comparison of the mean (average) concentration or 
value (based on a minimum of four replicate measurements) of an 
indicator parameter with its initial background concentration or value. 
The calculated value of the t-statistic must then be compared to the 
value of the t-statistic found in a table for t-test of significance at 
the specified level of significance. A calculated value of t which 
exceeds the value of t found in the table indicates a statistically 
significant change in the concentration or value of the indicator 
parameter.
    Formulae for calculation of the t-statistic and tables for t-test of 
significance can be found in most introductory statistics texts.

   Appendix V to Part 265--Examples of Potentially Incompatible Waste

    Many hazardous wastes, when mixed with other waste or materials at a 
hazardous waste facility, can produce effects which are harmful to human 
health and the environment, such as (1) heat or pressure, (2) fire or 
explosion, (3) violent reaction, (4) toxic dusts, mists, fumes, or 
gases, or (5) flammable fumes or gases.
    Below are examples of potentially incompatible wastes, waste 
components, and materials, along with the harmful consequences which 
result from mixing materials in one group with materials in another 
group. The list is intended as a guide to owners or operators of 
treatment, storage, and disposal facilities, and to enforcement and 
permit granting officials, to indicate the need for special precautions 
when managing these potentially incompatible waste materials or 
components.
    This list is not intended to be exhaustive. An owner or operator 
must, as the regulations require, adequately analyze his wastes so that 
he can avoid creating uncontrolled substances or reactions of the type 
listed below, whether they are listed below or not.
    It is possible for potentially incompatible wastes to be mixed in a 
way that precludes a reaction (e.g., adding acid to water rather than 
water to acid) or that neutralizes them (e.g., a strong acid mixed with 
a strong base), or that controls substances produced (e.g., by 
generating flammable gases in a closed tank equipped so that ignition 
cannot occur, and burning the gases in an incinerator).
    In the lists below, the mixing of a Group A material with a Group B 
material may have the potential consequence as noted.

------------------------------------------------------------------------
               Group 1-A                            Group 1-B           
------------------------------------------------------------------------
Acetylene sludge                         Acid sludge                    
Akaline caustic liquids                  Acid and water                 
Alkaline cleaner                         Battery acid                   
Alkaline corrosive liquids               Chemical cleaners              
Alkaline corrosive battery fluid         Electrolyte, acid              
Caustic wastewater                       Etching acid liquid or solvent 
Lime sludge and other corrosive                                         
 alkalines                                                              
Lime wastewater                          Pickling liquor and other      
                                          corrosive acids               
Lime and water                           Spent acid                     
Spent caustic                            Spent mixed acid               
                                         Spent sulfuric acid            
------------------------------------------------------------------------

    Potential consequences: Heat generation; violent reaction.

[[Page 504]]



------------------------------------------------------------------------
               Group 2-A                            Group 2-B           
------------------------------------------------------------------------
Aluminum                                 Any waste in Group 1-A or 1-B  
Beryllium                                                               
Calcium                                                                 
Lithium                                                                 
Magnesium                                                               
Potassium                                                               
Sodium                                                                  
Zinc powder                                                             
Other reactive metals and metal                                         
 hydrides                                                               
------------------------------------------------------------------------

    Potential consequences: Fire or explosion; generation of flammable 
hydrogen gas.

------------------------------------------------------------------------
               Group 3-A                            Group 3-B           
------------------------------------------------------------------------
Alcohols                                 Any concentrated waste in      
                                          Groups 1-A or 1-B             
Water                                    Calcium                        
                                         Lithium                        
                                         Metal hydrides                 
                                         Potassium                      
                                         SO2Cl2,!SOCl2, PCl3, CH3SiCl3  
                                         Other water-reactive waste     
------------------------------------------------------------------------

    Potential consequences: Fire, explosion, or heat generation; 
generation of flammable or toxic gases.

------------------------------------------------------------------------
               Group 4-A                            Group 4-B           
------------------------------------------------------------------------
Alcohols                                 Concentrated Group 1-A or 1-B  
                                          wastes                        
Aldehydes                                Group 2-A wastes               
Halogenated hydrocarbons                                                
Nitrated hydrocarbons                                                   
Unsaturated hydrocarbons                                                
Other reactive organic compounds and                                    
 solvents                                                               
------------------------------------------------------------------------

    Potential consequences: Fire, explosion, or violent reaction.

------------------------------------------------------------------------
               Group 5-A                            Group 5-B           
------------------------------------------------------------------------
Spent cyanide and sulfide solutions      Group 1-B wastes               
------------------------------------------------------------------------

    Potential consequences: Generation of toxic hydrogen cyanide or 
hydrogen sulfide gas.

------------------------------------------------------------------------
               Group 6-A                            Group 6-B           
------------------------------------------------------------------------
Chlorates                                Acetic acid and other organic  
                                          acids                         
Chlorine                                 Concentrated mineral acids     
Chlorites                                Group 2-A wastes               
Chromic acid                             Group 4-A wastes               
Hyphochlorites                           Other flammable and combustible
                                          wastes                        
Nitrates                                                                
Nitric acid, fuming                                                     
Perchlorates                                                            
Permanganates                                                           
Peroxides                                                               
Other strong oxidizers                                                  
------------------------------------------------------------------------

    Potential consequences: Fire, explosion, or violent reaction.
    Source: ``Law, Regulations, and Guidelines for Handling of Hazardous 
Waste.'' California Department of Health, February 1975.