Category Archives: Prop 65

Trichloroethylene is now officially an EPA carcinogen

EPA added TCE into its Integrated Risk Information System (IRIS) as a known carcinogen several days ago. Interestingly enough, TCE – a common chlorinated solvent found in contaminated groundwater and in Superfund sites – was listed as a cancer causing agent under California’s Prop 65 law way back in 1988.

Visit our website for our 2-day environmental seminars covering Federal and California regulations.


It is official now – Marijuana smoke is now on the Prop 65 list!

On March 21, 2009, I reported that California was considering adding marijuana smoke to the Prop 65 list. Well – it is official now.

The Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency is adding marijuana smoke to the Proposition 65 list1, effective June 19, 2009.

Marijuana smoke was considered by the Carcinogen Identification Committee (CIC) of the OEHHA Science Advisory Board2 at a public meeting held on May 29, 2009. The CIC determined that marijuana smoke was clearly shown, through scientifically valid testing according to generally accepted principles, to cause cancer. Consequently, marijuana smoke is being added to the Proposition 65 list, pursuant to Title 27, California Code of Regulations, section 25305(a)(1) (formerly Title 22, California Code of Regulations, section 12305(a)(1)).

The photos below are those of a car I came across in Washington State. It obviously belongs to a person who has very strongly held views about the aforementioned botanical plant recently regulated by California’s OEHHA.





It is official (almost) that marijuana smoke is carcinogenic

California EPA has issued a draft study indicating that there is some evidence from studies in humans that marijuana smoke is associated with increased cancer risk. Studies in animals also provide some evidence that marijuana smoke induces tumors, with benign and malignant tumors observed in rats exposed via inhalation, malignant tumors in rats exposed via subcutaneous injection as newborns, and benign tumors in mice exposed dermally. Studies investigating the genotoxicity, immunotoxicity, and effects on endocrine function and cell signaling pathways provide additional evidence for the carcinogenicity of marijuana smoke. Finally, the similarities in chemical composition and in toxicological activity between marijuana smoke and tobacco smoke, and the presence of numerous carcinogens in marijuana (and tobacco) smoke, provide additional evidence of carcinogenicity.

This study is the initial step in the process of listing marijuana smoke as a Prop 65 chemical due to its carcinogenicity. Tobacco smoke is already on the Prop 65 list.

New Prop 65 chemical proposed in California

California has proposed to add methanol to the list of Prop 65 chemicals. Prop 65 is also known as the Safe Drinking Water and Toxic Enforcement Act of 1986. The State of Califonia considers methanol to be a chemical that causes reproductive toxicity – one of the criteria that would require it to be listed as a Prop 65 chemical.

Comments as to whether methanol meets the criteria for listing provided in Title 27, Cal. Code of Regs., section 25306, along with any supporting documentation, should be sent to:

Ms. Cynthia Oshita, Office of Environmental Health Hazard Assessment Street Address: 1001 I Street Sacramento, California 95814 Mailing Address: P.O. Box 4010 Sacramento, California 95812-4010 Fax No.: (916) 323-8803; Telephone: (916) 445-6900; E-Mail:

Comments may also be delivered in person or by courier to the above address. In order to be considered, comments must be received at OEHHA by 5:00 p.m. on Monday, February 2, 2009.

If and when this chemical is added to the list, industry will have one year to comply with the warning requirements udner the state law. 

Prop 65 is one of the topics that are covered in Norman’s 2-day California Environmental Seminar on February 2-3, 2009.