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Chloramphenicol Delisted Effective January 4, 2013 From the List of Chemicals Known to the State of California to Cause Cancer

The California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) is removing chloramphenicol [CAS No. 56-75-7] from the list of chemicals known to the state to cause cancer, for purposes of Proposition 651.  The delisting of chloramphenicol is effective JANUARY 4, 2013. 

Chloramphenicol was originally added to the Proposition 65 list on October 1, 1989 pursuant to Labor Code Section 6382(d), which is incorporated by reference as a Proposition 65 listing mechanism by Health and Safety Code Section 25249.8(a).  Labor Code Section 6382(d) requires OEHHA to add chemicals known to cause cancer that are “within the scope of the federal Hazard Communication Standard (29 CFR 1910.1200)” to the Proposition 65 list. 

Chloramphenicol was listed based on its identification by the International Agency for Research on Cancer as a Group 2B chemical:  Possibly carcinogenic to humans in 1982, based on limited evidence of carcinogenicity in humans and inadequate evidence in animals (IARC, 1982).   

OEHHA’s removal of this chemical from the Proposition 65 list is required by a recent decision by the Third District Court of Appeal in the Styrene Information and Research Council v. The Office of Environmental Health Hazard Assessment2.  The Appellate court held that OEHHA may not list a chemical as causing cancer under Proposition 65 pursuant to Labor Code section 6382(d), solely on the basis of its identification by the International Agency for Research on Cancer (IARC) as being possibly carcinogenic to humans (Group 2B), where that determination is based on less than sufficient evidence of carcinogenicity in humans and animals.  Therefore, chloramphenicol is being removed from the list at this time.  No other basis for listing has been identified by OEHHA.

Footnotes and References

International Agency for Research on Cancer (IARC, 1982). IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans.  Chemicals, Industrial Processes and Industries Associated with Cancer in Humans.  IARC Monographs, Volumes 1 to 29.  IARC Monographs Supplement 4, pp. 18, 79-80.   IARC, Lyon France.  Available at URL: http://monographs.iarc.fr/ENG/Monographs/suppl4/index.php [Accessed December 10, 2012].

1Commonly known as Proposition 65, the Safe Drinking Water and Toxic Enforcement Act of 1986 is codified in Health and Safety Code section 25249.5 et seq.

2SIRC v OEHHA (Nov. 15, 2012) Westlaw No. 5834844