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α-Methyl styrene Listed Effective July 29, 2011 as Known to the State of California to Cause Reproductive Toxicity

The Office of Environmental Health Hazard Assessment (OEHHA) within the California Environmental Protection Agency is adding α-methyl styrene (CAS No. 98-83-9) to the list of chemicals known to the state to cause reproductive toxicity for purposes of the Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65)1.  The listing of α-methyl styrene for the endpoint of female reproductive toxicity is effective July 29, 2011. 

Health and Safety Code section 25249.8(a) requires that substances identified in Labor Code section 6382(d) as causing reproductive toxicity be included on the Proposition 65 list.  Labor Code section 6382(d) captures any chemicals within the scope of the federal Hazard Communication Standard that are identified as reproductive toxicants.  Chemicals fall within the scope of the Hazard Communication Standard if they are listed as hazardous in the latest edition of the American Conference of Governmental Industrial Hygienists’ (ACGIH) “Threshold Limit Values (TLVs).”  The TLV for α-methyl styrene (female endpoint) was established on the basis of ACGIH’s findings of female reproductive damage. 

The basis for the listing of α-methyl styrene was described in a public notice published in the May 27, 2011, issue of the California Regulatory Notice Register (Register 2011, No. 21-Z).  The title of the notice was “Notice of Intent to List Alpha-Methyl Styrene by the Labor Code Mechanism".  The publication of the notice initiated a 30-day public comment period that closed on June 27, 2011.

Chemical

CAS No.

Toxicological Endpoint

Listing Mechanism2
α-Methyl styrene
98-83-9
female reproductive toxicity
LC

Footnotes and References

1Health and Safety Code, section 25249.5 et seq.

2Listing mechanism:  LC – “Labor Code” mechanism (Labor Code sections 6382(b)(1) and (d))