Chemicals Listed As Known to the State to Cause Cancer (Megestrol Acetate) and Reproductive Toxicity (Methyl Isobutyl Ketone)

Effective March 28, 2014, the Office of Environmental Health Hazard Assessment (OEHHA) is adding methyl isobutyl ketone (MIBK) to the list of chemicals known to the State to cause reproductive toxicity for purposes of Proposition 65¹.

The listing of methyl isobutyl ketone is based on formal identification by the U.S. Environmental Protection Agency (U.S. EPA), an authoritative body², that the chemical causes reproductive toxicity (developmental endpoint).  The criteria used by OEHHA for the listing of chemicals under the “authoritative bodies” mechanism can be found in Title 27, Cal. Code of Regs., section 25306. 

The documentation supporting OEHHA’s determination that the criteria for administrative listing have been satisfied for methyl isobutyl ketone is included in the Notice of Intent to List posted on OEHHA’s website and published in the September 6, 2013 issue of the California Regulatory Notice Register (Register 2013, No. 36-Z).  OEHHA received one public comment on the Notice of Intent to List.  That comment and OEHHA’s response to it are posted with the Notice of Intent to List.

In summary, methyl isobutyl ketone is being listed under Proposition 65 as known to the State to cause reproductive toxicity, as follows:

Effective March 28, 2014, the Office of Environmental Health Hazard Assessment (OEHHA) is adding megestrol acetate to the list of chemicals known to the State to cause cancer for purposes of Proposition 65.    

The listing of megestrol acetate is based on a formal requirement by a state or federal agency that the chemical be identified or labeled as causing cancer⁴ as provided under the Act.  Megestrol acetate has been identified or labeled to communicate a risk of cancer in accordance with formal requirements by the U.S. Food and Drug Administration.   Regulations governing the listing of chemicals under the “formally required to be labeled or identified” mechanism are published in Title 27, California Code of Regulations, section 25902. 

The documentation supporting OEHHA’s determination that the criteria for administrative listing have been satisfied for megestrol acetate is included in the Notice of Intent to List A Chemical by the “Formally Required to Be Labeled or Identified” Mechanism:  Megestrol Acetate, published in the February 7, 2014 issue of the California Regulatory Notice Register (Register 2014, No. 6-Z).  No public comments were received. 

In summary, the following chemical is listed under Proposition 65 as known to the State to  cause cancer:

Downloads

Listing Notice for Methyl Isobutyl Ketone (MIBK)
Mar 28, 2014

Listing Notice for Megestrol Acetate
Mar 28, 2014

Chemical Reference

• Methyl Isobutyl Ketone (MIBK)
• Megestrol Acetate

Related Notices

• Notice of Intent to List: Methyl Isobutyl Ketone

  Sep 6, 2013
• Notice of Intent to List: Megestrol Acetate

  Feb 7, 2014
• Request for Relevant Information on Chemical Being Considered for Listing by the Authoritative Bodies Mechanism: Methyl Isobutyl Ketone

  Mar 15, 2013

Footnotes and References

Footnotes

¹ The Safe Drinking Water and Toxic Enforcement Act of 1986, Health and Safety Code section 25249.5 et seq.

² See Health and Safety Code, section 25249.8(b) and Title 27, Cal. Code of Regs., section 25306.

³ Listing mechanism:  AB – “authoritative bodies” mechanism (Title 27, Cal. Code of Regs. section 25306).

⁴ See Health and Safety Code section 25249.8(b) and Title 27, Cal. Code of Regs., section 25902.

⁵ Listing mechanism: FR – “formally required to be labeled or identified” mechanism (Health and Safety Code section 25249.8(b) and Title 27 Cal. Code of Regs., section 25902).