Toxic Air Contaminant Identification List
This page last reviewed July 18, 2011
This page provides information
on substances identified as California toxic air contaminants.
Title 17, CCR, § 93000. Substances Identified As Toxic Air Contaminants.
Each substance identified in this section has been determined by the State Board to be a toxic air contaminant as defined in Health and Safety Code section 39655. If the State Board has found there to be a threshold exposure level below which no significant adverse health effects are anticipated from exposure to the identified substance, that level is specified as the threshold determination. If the Board has found there to be no threshold exposure level below which no significant adverse health effects are anticipated from exposure to the identified substance, a determination of "no threshold" is specified. If the Board has found that there is not sufficient available scientific evidence to support the identification of a threshold exposure level, the "Threshold" column specifies "None identified."
|Benzene (C6H6)||None identified|
|Ethylene Dibromide (BrCH2CH2Br; 1,2-dibromoethane)||None identified|
|Ethylene Dichloride (ClCH2CH2Cl; 1,2-dichloroethane)||None identified|
|Hexavalent chromium (Cr (VI))||None identified|
|Asbestos [asbestiform varieties of serpentine (chrysotile), riebeckite (crocidolite),cummingtonite-grunerite (amosite), tremolite, actinolite, and anthophyllite]||None identified|
|Dibenzo-p-dioxins and Dibenzofurans chlorinated in the 2,3,7 and 8 positions and containing 4,5,6 or 7 chlorine atoms||None identified|
|Cadmium (metallic cadmium and cadmium compounds)||None identified|
|Carbon Tetrachloride(CCl4; tetrachloromethane)||None identified|
|Ethylene Oxide (1,2-epoxyethane)||None identified|
|Methylene Chloride (CH2Cl2; Dichloromethane)||None identified|
|Trichloroethylene (CCl2CHCl; Trichloroethene)||None identified|
|Chloroform (CHCl3)||None identified|
|Vinyl chloride (C2H3Cl; Chloroethylene)||None identified|
|Inorganic Arsenic||None identified|
|Nickel (metallic nickel and inorganic nickel compounds)||None identified|
|Perchloroethylene (C2Cl4; Tetrachloroethylene)||None identified|
|Formaldehyde (HCHO)||None identified|
|1,3-Butadiene (C4H6)||None identified|
|Inorganic Lead||None identified|
|Particulate Emissions from Diesel-Fueled Engines||None identified|
|Environmental Tobacco Smoke||None identified|
Note: Authority cited: Sections 39600, 39601 and 39662, Health and Safety Code. Reference: Sections 39650, 39660, 39661 and 39662, Health and Safety Code.
- New section filed 9-23-85; effective thirtieth day thereafter
(Register 85, No. 39). For history of former subchapter 7, see
Registers 84, No. 10;
83, No. 2; 81, No. 48; 77,
No. 12; and 74, No. 47.
- Amendment filed 1-14-86; effective thirtieth day thereafter (Register 86, No. 3).
- Amendment filed 2-10-86; effective thirtieth day thereafter (Register 86,
- Amendment filed 10-9-86; effective thirtieth day thereafter (Register 86, No. 43).
- Amendment filed 11-25-86; effective thirtieth day thereafter (Register 86, No. 48).
- Amendment filed 2-23-87; effective thirtieth day thereafter (Register 87, No. 9).
- Amendment filed 10-8-87; operative 11-7-87 (Register 87, No. 43).
- Amendment filed 3-15-88; operative 4-14-88 (Register 88, No. 13).
- Amendment filed 7-22-88; operative 8-21-88 (Register 88, No. 31).
- Amendment adding Methylene Chloride filed 6-7-90; operative 7-7-90 (Register 90, No. 30).
- Amendment adding Trichloroethylene filed 2-27-91; operative 3-29-91 (Register 91, No. 13).
- Amendment adding Vinyl chloride filed 5-10-91; operative 6-9-91 (Register
91, No. 25).
- Editorial correction, including removal of Inorganic arsenic (Register 91, No. 25).
- Amendment adding Chloroform filed 5-10-91; operative 6-9-91 (Register 91, No. 25).
- Amendment adding Inorganic Arsenic filed 6-6-91; operative 7-6-91 (Register
91, No. 26).
- Change without regulatory effect amending Trichloroethylene and adding
Nickel filed 7-14-92 pursuant to
title 1, California Code of
Regulations (Register 92, No. 29).
- Amendment adding Perchloroethylene filed 10-2-92; operative 11-1-92 (Register 92, No. 40).
- Amendment adding Formaldehyde filed 3-2-93; operative 4-1-93 (Register 93,
- Amendment adding 1,3-Butadiene filed 4-14-93; operative 5-14-93 (Register
93, No. 16).
- Editorial correction (Register 98, No. 16).
- Amendment adding inorganic lead filed 4-14-98; operative 5-14-98 (Register
98, No. 16).
- Amendment adding "Particulate Emissions from Diesel-Fueled Engines" filed
7-21-99; operative 8-20-99 (Register 99, No. 30).
- Amendment adding "Environmental Tobacco Smoke" filed 1-9-2007; operative 2-
8-2007 (Register 2007, No. 2).
Title 17, CCR, § 93001. Hazardous Air
Pollutants Identified as Toxic Air Contaminants
Each substance listed in this section has been identified as a hazardous air pollutant pursuant to subsection (b) of Section 112 of the federal Clean Air Act (42 U.S.C. Section 7412(b)) and has been designated by the State Board to be a toxic air contaminant pursuant to Health and Safety Code Section 39657.
Benzene (including benzene from gasoline)
Bis (2-ethylhexyl) phthalate (DEHP)
Bis (chloromethyl) ether
Chloromethyl methyl ether
Cresols/Cresylic acid (isomers and mixture)
2,4-D, salts and esters
Dichloroethyl ether (Bis (2-chloroethyl) ether)
N.N-Diethyl aniline (N.N-Dimethylaniline)
Dimethyl carbamoyl chloride
4,6-Dinitro-o-cresol, and salts
Ethyl carbamate (Urethane)
Ethyl chloride (Chloroethane)
Ethylene dibromide (Dibromoethane)
Ethylene dichloride (1,2-Dichloroethane)
Ethylene imine (Aziridine)
Ethylidene dichloride (1,1-Dichloroethane)
Hydrogen fluoride (Hydrofluoric acid)
Lindane (all isomers)
Methyl bromide (Bromomethane)
Methyl chloride (Chloromethane)
Methyl chloroform (1,1,1-Trichloroethane)
Methyl ethyl ketone (2-Butanone)
Methyl iodide (Iodomethane)
Methyl isobutyl ketone (Hexone)
Methyl tert butyl ether
Methylene chloride (Dichloromethane)
Methylene diphenyl diisocyanate (MDI)
Polychlorinated biphenyls (Aroclors)
Prophylene dichloride (1,2-Dichloropropane)
Toxaphene (chlorinated camphene)
Vinylidene chloride (1,1-Dichloroethylene)
Xylenes (isomers and mixture)
Arsenic Compounds (inorganic including arsine)
Coke Oven Emissions
Cyanide Compounds [FN1]
Glycol ethers [FN2]
Fine mineral fibers [FN3]
Polycyclic Organic Matter [FN4]
Radionuclides (including radon) [FN5]
Note: For all listing above which contain the word "compounds" and for glycol ethers, the following applies: Unless otherwise specified, these listings are defined as including any unique chemical substance that contains the named chemical (i.e., antimony, arsenic, etc) as part of that chemical's infrastructure.
X'CN where X = H' or
any other group where a formal dissociation may occur. For example KCN
or Ca(CN) 2
[FN2] includes mono- and di-ethers of ethylene glycol, diethylene glycol, and triethylene glycol (R(OCH 2 CH 2) n -OR' where
n = 1,2 or 3
R = alkyl or aryl groups
R' = R, H, or groups which, when removed, yield glycol ethers with the structure; R(OCH2CH)n -OH. Polymers are excluded from the glycol category.
[FN3] includes mineral fiber emissions from facilities manufacturing or processing glass, rock, or slag fibers (or other mineral derived fibers) of average diameter 1 micrometer or less.
[FN4] includes organic compounds with more than one benzene ring, and which have a boiling point greater than or equal to 100 degrees °C
[FN5] a type of atom which spontaneously undergoes radioactive decay.
Note: Authority cited: Sections 39657, 39600, 39601 and 39662, Health and Safety Code. Reference: Sections 39650, 39655, 39656, 39657, 39658, 39659, 39660, 39661 and 39662, Health and Safety Code.
- New section filed 3-9-94; operative 4-8-94. Submitted to OAL for printing only (Register 94, No. 10).