air toxics

Air toxic

Agency for Toxic Substances and Disease Registry
Minimum Risk Levels (MRLs)

A MRL is an estimate of the daily human exposure to a hazardous substance that is likely to be without appreciable risk of adverse non cancer health effects over a specified duration of exposure. MRLs are developed by the Agency for Toxic Substances and Disease Registry under the Centers for Disease Control and Prevention.

The following are the pollutants in the 1999 Alaska Air Toxics Emission Inventory considered to be some of the most toxic for non-cancer effects as they correspond to the the ten lowest minimum risk levels:

Rank
Chemical Name
Inhalation risk - mg/m 3
oral risk - mg/kg/day
Comments
1
2,3,7,8-Tetrachlorodibenzo-p-Dioxin (PDF)
n/a
0.000000001
n/a
2
Cobalt Compounds (PDF)
0.00003
n/a
n/a
3
Titanium Tetrachloride (PDF)
0.0001
n/a
n/a
4
Nickel Compounds (PDF)
0.0002
n/a
n/a
5
Radionuclides (including uranium, radium, and radon) (PDF)
0.0003
n/a
MRL determined for uranium
6
1,1-Dimethyl Hydrazine (PDF)
0.0005
n/a
n/a
7
Toxaphene (Chlorinated Camphene) (PDF)
n/a
0.001
n/a
8
Bis(chloromethyl)ether (PDF)
0.0014
n/a
n/a
9
1,2-Dibromo-3-Chloropropane (PDF)
n/a
0.002
n/a
10
Formaldehyde (PDF)
0.004
n/a
n/a
11
4,6-Dinitro-o-Cresol, and Salts (PDF)
n/a
0.004
n/a

 

The following pollutants in the 1999 Alaska Air Toxics Emission Inventory also have MRLs:

  • Hydrazine
  • Phosphorus
  • 4,4'-Methylenedianiline
  • Dichloroethyl ether (Bis[2-chloroethyl]ether)
  • Propylene dichloride (1,2-Dichloropropane)
  • Benzene (including benzene from gasoline)
  • Ethylene oxide
  • Tetrachloroethylene (Perchloroethylene)
  • Xylenes (mixture)
  • 1,4-Dichlorobenzene(p)
  • Chloroform
  • Trichloroethylene
  • Ethylene dichloride (1,2-Dichloroethane)
  • 1,1,2,2-Tetrachloroethane
  • Hexachloroethane
  • To explore the possible health effects of these and other pollutants, please visit the following internet sites:

  • https://www.epa.gov/iris - The Environmental Protection Agency's list of non-cancer and cancer risk values for many pollutants.
  • https://www.atsdr.cdc.gov/index.html - The Agency for Toxic Substances and Disease Registry list of pollutants and corresponding Minimum Risk Levels.
  • http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?HSDB - The National Institutes of Health, National Library of Medicine's toxicology data file focusing on the toxicology of potentially hazardous chemicals.
  • https://www.epa.gov/haps/health-effects-notebook-hazardous-air-pollutants - The Environmental Protection Agency's list of hazardous air pollutants, including summaries of uses, sources and potential health effects.
  • https://www.atsdr.cdc.gov/toxfaqs/index.asp - The Agency for Toxic Substances and Disease Registry list of Frequently Asked Questions about contaminants found at Hazardous Waste Sites.