December 13, 2019

Draft Toxicological Profiles for Chlorobenzene, Other Chemicals Published

A new draft toxicological profile for chlorobenzene is now available for review and public comment from the Agency for Toxic Substances and Disease Registry. According to ATSDR, chlorobenzene is used as a solvent for some pesticide formulations, as a degreaser, and as a chemical intermediate to make other chemicals. Individuals who work where chlorobenzene is made or used could be exposed by breathing air with chlorobenzene vapors or by spilling or splashing the chemical on their skin. ATSDR warns that high levels of chlorobenzene can damage the liver and kidneys and affect the brain. The agency notes that workers exposed to high levels of chlorobenzene in the air reported health effects such as headaches, nausea, sleepiness, numbness, and vomiting. However, the workers may also have been exposed to other chemicals that could have contributed to or caused these effects.

OSHA’s permissible exposure limit for chlorobenzene is 75 ppm, or 350 mg/m3, as an eight-hour time-weighted average. The Cal/OSHA PEL and the ACGIH Threshold Limit Value are lower; both organizations’ recommended limits for chlorobenzene are 10 ppm. NIOSH has not established a recommended exposure limit for chlorobenzene, but in 1988 the agency provided comments to OSHA questioning whether the PEL was adequate to protect workers from recognized health hazards.

New draft toxicological profiles are also available for the pesticide dichlorodiphenyltrichloroethane, or DDT; di(2-ethylhexyl)phthalate, or DEHP, which is found in many plastics; the industrial chemical 1,1-dichloroethene; 1,2-dichloropropane, which is primarily used to make other chlorinated chemicals; hexachlorobutadiene, which is used to make rubber compounds, as a solvent, and to make lubricants; and 1,1,2-trichloroethane, which is primarily used as a solvent and a chemical intermediate. Comments on the draft profiles are due by March 5, 2020. More information on submitting comments is available in the Federal Register.

ATSDR toxicological profiles characterize the toxicology and adverse health effects information for hazardous substances. Each peer-reviewed profile identifies and reviews the key literature that describes a substance's toxicological properties. Health and toxicologic information on the potential for human exposure; chemical and physical properties; regulations and guidelines; and production, import, use, and disposal can also be found in ATSDR’s toxicological profiles. A full list of toxic substances with published profiles is available on the agency’s website.