Federal regulations · Through 2026-08-25 · Newer source version available

40 CFR Appendix IV to Part 266: Appendix IV to Part 266—Reference Air Concentrations*

Constituent CAS No. RAC (ug/m3)
Acetaldehyde 75-07-0 10
Acetonitrile 75-05-8 10
Acetophenone 98-86-2 100
Acrolein 107-02-8 20
Aldicarb 116-06-3 1
Aluminum Phosphide 20859-73-8 0.3
Allyl Alcohol 107-18-6 5
Antimony 7440-36-0 0.3
Barium 7440-39-3 50
Barium Cyanide 542-62-1 50
Bromomethane 74-83-9 0.8
Calcium Cyanide 592-01-8 30
Carbon Disulfide 75-15-0 200
Chloral 75-87-6 2
Chlorine (free) 0.4
2-Chloro-1,3-butadiene 126-99-8 3
Chromium III 16065-83-1 1000
Copper Cyanide 544-92-3 5
Cresols 1319-77-3 50
Cumene 98-82-8 1
Cyanide (free) 57-12-15 20
Cyanogen 460-19-5 30
Cyanogen Bromide 506-68-3 80
Di-n-butyl Phthalate 84-74-2 100
o-Dichlorobenzene 95-50-1 10
p-Dichlorobenzene 106-46-7 10
Dichlorodifluoromethane 75-71-8 200
2,4-Dichlorophenol 120-83-2 3
Diethyl Phthalate 84-66-2 800
Dimethoate 60-51-5 0.8
2,4-Dinitrophenol 51-28-5 2
Dinoseb 88-85-7 0.9
Diphenylamine 122-39-4 20
Endosulfan 115-29-1 0.05
Endrin 72-20-8 0.3
Fluorine 7782-41-4 50
Formic Acid 64-18-6 2000
Glycidyaldehyde 765-34-4 0.3
Hexachlorocyclopentadiene 77-47-4 5
Hexachlorophene 70-30-4 0.3
Hydrocyanic Acid 74-90-8 20
Hydrogen Chloride 7647-01-1 7
Hydrogen Sulfide 7783-06-4 3
Isobutyl Alcohol 78-83-1 300
Lead 7439-92-1 0.09
Maleic Anhydride 108-31-6 100
Mercury 7439-97-6 0.3
Methacrylonitrile 126-98-7 0.1
Methomyl 16752-77-5 20
Methoxychlor 72-43-5 50
Methyl Chlorocarbonate 79-22-1 1000
Methyl Ethyl Ketone 78-93-3 80
Methyl Parathion 298-00-0 0.3
Nickel Cyanide 557-19-7 20
Nitric Oxide 10102-43-9 100
Nitrobenzene 98-95-3 0.8
Pentachlorobenzene 608-93-5 0.8
Pentachlorophenol 87-86-5 30
Phenol 108-95-2 30
M-Phenylenediamine 108-45-2 5
Phenylmercuric Acetate 62-38-4 0.075
Phosphine 7803-51-2 0.3
Phthalic Anhydride 85-44-9 2000
Potassium Cyanide 151-50-8 50
Potassium Silver Cyanide 506-61-6 200
Pyridine 110-86-1 1
Selenious Acid 7783-60-8 3
Selenourea 630-10-4 5
Silver 7440-22-4 3
Silver Cyanide 506-64-9 100
Sodium Cyanide 143-33-9 30
Strychnine 57-24-9 0.3
1,2,4,5-Tetrachlorobenzene 95-94-3 0.3
2,3,4,6-Tetrachlorophenol 58-90-2 30
Tetraethyl Lead 78-00-2 0.0001
Tetrahydrofuran 109-99-9 10
Thallic Oxide 1314-32-5 0.3
Thallium 7440-28-0 0.5
Thallium (I) Acetate 563-68-8 0.5
Thallium (I) Carbonate 6533-73-9 0.3
Thallium (I) Chloride 7791-12-0 0.3
Thallium (I) Nitrate 10102-45-1 0.5
Thallium Selenite 12039-52-0 0.5
Thallium (I) Sulfate 7446-18-6 0.075
Thiram 137-26-8 5
Toluene 108-88-3 300
1,2,4-Trichlorobenzene 120-82-1 20
Trichloromonofluoromethane 75-69-4 300
2,4,5-Trichlorophenol 95-95-4 100
Vanadium Pentoxide 1314-62-1 20
Warfarin 81-81-2 0.3
Xylenes 1330-20-7 80
Zinc Cyanide 557-21-1 50
Zinc Phosphide 1314-84-7 0.3
*The RAC for other appendix VIII part 261 constituents not listed herein or in appendix V of this part is 0.1 ug/m. 3

Where this section sits in the code

Title 40—Protection of Environment
CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY
SUBCHAPTER I—SOLID WASTES
PART 266—STANDARDS FOR THE MANAGEMENT OF SPECIFIC HAZARDOUS WASTES AND SPECIFIC TYPES OF HAZARDOUS WASTE MANAGEMENT FACILITIES

Constituent CAS No. RAC (ug/m3)

Acetaldehyde 75-07-0 10

Acetonitrile 75-05-8 10

Acetophenone 98-86-2 100

Acrolein 107-02-8 20

Aldicarb 116-06-3 1

Aluminum Phosphide 20859-73-8 0.3

Allyl Alcohol 107-18-6 5

Antimony 7440-36-0 0.3

Barium 7440-39-3 50

Barium Cyanide 542-62-1 50

Bromomethane 74-83-9 0.8

Calcium Cyanide 592-01-8 30

Carbon Disulfide 75-15-0 200

Chloral 75-87-6 2

Chlorine (free) 0.4

2-Chloro-1,3-butadiene 126-99-8 3

Chromium III 16065-83-1 1000

Copper Cyanide 544-92-3 5

Cresols 1319-77-3 50

Cumene 98-82-8 1

Cyanide (free) 57-12-15 20

Cyanogen 460-19-5 30

Cyanogen Bromide 506-68-3 80

Di-n-butyl Phthalate 84-74-2 100

o-Dichlorobenzene 95-50-1 10

p-Dichlorobenzene 106-46-7 10

Dichlorodifluoromethane 75-71-8 200

2,4-Dichlorophenol 120-83-2 3

Diethyl Phthalate 84-66-2 800

Dimethoate 60-51-5 0.8

2,4-Dinitrophenol 51-28-5 2

Dinoseb 88-85-7 0.9

Diphenylamine 122-39-4 20

Endosulfan 115-29-1 0.05

Endrin 72-20-8 0.3

Fluorine 7782-41-4 50

Formic Acid 64-18-6 2000

Glycidyaldehyde 765-34-4 0.3

Hexachlorocyclopentadiene 77-47-4 5

Hexachlorophene 70-30-4 0.3

Hydrocyanic Acid 74-90-8 20

Hydrogen Chloride 7647-01-1 7

Hydrogen Sulfide 7783-06-4 3

Isobutyl Alcohol 78-83-1 300

Lead 7439-92-1 0.09

Maleic Anhydride 108-31-6 100

Mercury 7439-97-6 0.3

Methacrylonitrile 126-98-7 0.1

Methomyl 16752-77-5 20

Methoxychlor 72-43-5 50

Methyl Chlorocarbonate 79-22-1 1000

Methyl Ethyl Ketone 78-93-3 80

Methyl Parathion 298-00-0 0.3

Nickel Cyanide 557-19-7 20

Nitric Oxide 10102-43-9 100

Nitrobenzene 98-95-3 0.8

Pentachlorobenzene 608-93-5 0.8

Pentachlorophenol 87-86-5 30

Phenol 108-95-2 30

M-Phenylenediamine 108-45-2 5

Phenylmercuric Acetate 62-38-4 0.075

Phosphine 7803-51-2 0.3

Phthalic Anhydride 85-44-9 2000

Potassium Cyanide 151-50-8 50

Potassium Silver Cyanide 506-61-6 200

Pyridine 110-86-1 1

Selenious Acid 7783-60-8 3

Selenourea 630-10-4 5

Silver 7440-22-4 3

Silver Cyanide 506-64-9 100

Sodium Cyanide 143-33-9 30

Strychnine 57-24-9 0.3

1,2,4,5-Tetrachlorobenzene 95-94-3 0.3

2,3,4,6-Tetrachlorophenol 58-90-2 30

Tetraethyl Lead 78-00-2 0.0001

Tetrahydrofuran 109-99-9 10

Thallic Oxide 1314-32-5 0.3

Thallium 7440-28-0 0.5

Thallium (I) Acetate 563-68-8 0.5

Thallium (I) Carbonate 6533-73-9 0.3

Thallium (I) Chloride 7791-12-0 0.3

Thallium (I) Nitrate 10102-45-1 0.5

Thallium Selenite 12039-52-0 0.5

Thallium (I) Sulfate 7446-18-6 0.075

Thiram 137-26-8 5

Toluene 108-88-3 300

1,2,4-Trichlorobenzene 120-82-1 20

Trichloromonofluoromethane 75-69-4 300

2,4,5-Trichlorophenol 95-95-4 100

Vanadium Pentoxide 1314-62-1 20

Warfarin 81-81-2 0.3

Xylenes 1330-20-7 80

Zinc Cyanide 557-21-1 50

Zinc Phosphide 1314-84-7 0.3

*The RAC for other appendix VIII part 261 constituents not listed herein or in appendix V of this part is 0.1 ug/m. 3

Collected 2026-08-27T02:26:04Z. Source file · JSON

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