November 5, 2020

Final Toxicological Profiles for Chlorobenzene, Other Chemicals Published

A final toxicological profile for the industrial chemical chlorobenzene is now available from the Agency for Toxic Substances and Disease Registry. According to ATSDR, chlorobenzene is used as a solvent for pesticide formulations, diisocyanate manufacture, and degreasing automobile parts. It is also used as a chemical intermediate to make other chemicals. The agency’s information on the uses of chlorobenzene comes from the 1980s; ATSDR explains that recent data regarding chlorobenzene uses “were not located.” Individuals who work where chlorobenzene is made or used could be exposed to the chemical in the air by breathing it in or through their skin.

Chlorobenzene is used in various occupational settings, but ATSDR states that there are limited biomonitoring data of populations potentially exposed to high levels of the chemical. Workers exposed to chlorobenzene in the air have reported health effects such as headaches, dizziness, and sleepiness. ATSDR warns that studies in laboratory animals indicate that high levels of chlorobenzene can damage the liver and kidneys and affect the nervous system.

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 2-butanone, 1,2-diphenylhydrazine, and mirex and chlordecone.

ATSDR’s toxicological profiles characterize the toxicological 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. 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.