The California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) has issued a notice addressing its amendment to “the calculation used to convert estimates of animal cancer potency to estimates of human cancer potency, which is used to calculate no significant risk levels for carcinogens listed under Proposition 65.”

According to the notice, the amendment took effect November 11, 2011, and will change “the existing regulatory provision to a ratio of human to animal bodyweight to the one-fourth power for interspecies conversion and delete[] the provision giving specific scaling factors for mice and rat data.”

OEHHA has also announced that its Carcinogen Identification Committee has been asked to consider whether Dibenzanthracenes should be added to the Proposition 65 list. These substances are ubiquitous polyaromatic hydrocarbons that are the product of incomplete combustion, and human exposure may occur from contaminated food or water. Public comments are requested by January 10, 2012.

In other action, OEHHA has posted “the comments of three external peer reviewers of the draft public health goal for perchlorate that was released for public comment in January 2011.” The comments were submitted by researchers from the Oregon Health & Science University, University of North Texas Health Sciences Center and University of Rochester School of Medicine and Dentistry. Perchlorate exposure in the United States mostly occurs from ingestion of contaminated food or water. The chemical is used in a variety of chemical processes.