NIOSH Potential Occupational Carcinogens

The effect of this new policy will be the development, whenever possible, of quantitative RELs that are based on human and/or animal data, as well as on the consideration of technological feasibility for controlling workplace exposures to the REL. Under the old policy, RELs for most carcinogens were non-quantitative values labeled lowest feasible concentration (LFC). [Note There are a few exceptions to LFC RELs for carcinogens (e.g., RELs for asbestos, formaldehyde, benzene, and ethylene oxide are quantitative values based primarily on analjdical limits of detection or technological feasibility). Also, in 1989, NIOSH adopted several quantitative RELs for carcinogens from OSHA s permissible exposure limit (PEL) update.] 

Under the new policy, NIOSH will also recommend the complete range of respirators (as determined by the NIOSH Respirator Decision Logic) for carcinogens with quantitative RELs. In this way, respirators will be consistently recommended regardless of whether a substance is a carcinogen or a non-carcinogen. 

In the past, NIOSH identified numerous substanees that should be treated as potential oeeupational carcinogens even though OSHA might not have identified them as such. Inf determining their carcinogenicity, NIOSH used the OSHA classification outlined in 29 CFR 1990.103, which states in part  

Potential occupational carcinogen means any substance, or combination or mixture of substances, which causes an increased incidence of benign and/or malignant neoplasms, or a substantial decrease in the latency period between exposure and onset of neoplasms in humans or in one or more experimental mammalian species as the result of any oral, respiratory or dermal exposure, or any other exposure which results in the induction of tumors at a site other than the site of administration. This definition also includes any substance which is metabolized into one or more potential occupational carcinogens by mammals. 

When thresholds for carcinogens that would protect 100% of the population had not been identified, NIOSH usually recommended that occupational exposures to carcinogens be limited to the lowest feasible concentration. To ensure maximum protection from carcinogens through the use of respiratory protection, NIOSH also recommended that only the most reliable and protective respirators be used. These respirators include (1) a self-contained breathing apparatus (SCBA) that has a full facepiece and is operated in a positive pressure mode, or (2) a supplied air respirator that has a full facepiece and is operated in a pressure demand or other positive pressure mode in combination with an auxiliary SCBA operated in a pressure demand or other positive pressure mode. 

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NIOSH (National Institute for Occupational Safety and Health). 2000. Appendix A NIOSH Pocket Guide to Chemical Hazards. NIOSH Potential Occupational Carcinogens. [Online], Available http //www.cdc.gov/niosh/npg/nengapdx.htm. [April 30, 2001]. 

Ethylene thiourea is toxic and known to produce thyroid neoplasms (thyroid hyperplasia) in rats and liver neoplasms in mice following long-term administration NIOSH potential occupational carcinogen NTP Suspect carcinogen OSHA Possible suspect carcinogen. Acute oral toxicity (LD50) 1832 mg/kg [Rat],... 

Ca = NIOSH potential occupational carcinogen (if no value listed, NIOSH recommends occupational exposure to the lowest feasible concentration)... 

Ca A notation used by NIOSH to indicate that a substance is considered a known or potential occupational carcinogen. 

NIOSH maintains a list of substances considered to be potential occupational carcinogens. 

The federal government is concerned about the amount of hexachloroethane that you are exposed to in the environment. The government has established standards and guidelines to prevent you from being overexposed. The Occupational Safety and Health Administration (OSHA) has set a limit of 1 part per million (ppm) for the hexachloroethane in workplace air over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) considers hexachloroethane as a potential occupational carcinogen (can cause cancer) and recommends 1 ppm in air as a tolerance value. 

Exposure limits (ppm) Potential occupational carcinogen. NIOSH REL TWA 1, 15-min ceiling 1, IDLH 85 OSHA PEL TWA 2, 15-min ceiling 10 ACGIH TLV TWA 2 (proposed). 

Exposure limits Potential occupational carcinogen. NIOSH REL IDLH 100 ppm OSHA PEL ... 

Exposure limits Potential occupational carcinogen. No individual standards have been set however, as a constituent in coal tar pitch volatiles, the following exposure limits have been established (mg/m ) NIOSH RET TWA 0.1 (cyclohexane-extractable fraction), IDLH 80 OSHA PEL TWA 0.2 (benzene-soluble fraction) ACGIH TLV TWA 0.2 (benzene solubles). 

Exposure limits (mg/m ) Potential occupational carcinogen. NIOSH REL TWA 5, STEP 10, IDLH 5,000 OSHA PEL TWA 5 ACGIH TLV TWA 5 (adopted). 

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