This notice is brought to you by the OEHHA.

The California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) intends to list the chemical hydrogen cyanide and cyanide salts as known to the State to cause reproductive toxicity (male reproductive toxicity endpoint) under the Safe Drinking Water and Toxic Enforcement Act of 1986.1 This action is being proposed under the authoritative bodies listing mechanism.

OEHHA requested information relevant to the possible listing of HCN and CN Salts in a notice published in the California Regulatory Notice Register on May 13, 2011 (Register 2011, Vol. No. 19Z). OEHHA received comments for this chemical.

OEHHA’s determination: Hydrogen Cyanide and Cyanide Salts meet the criteria for listing as known to the State to cause reproductive toxicity (male reproductive toxicity endpoint) under Proposition 65, based on findings of the U.S. EPA (U.S. EPA, 2010a; 2010b).

In 2010, U.S. EPA updated its online Integrated Risk Information System (IRIS) entry for hydrogen cyanide and cyanide salts (U.S. EPA, 2010a). The new oral chronic Reference Dose (RfD) of 0.0006 milligrams per kilogram bodyweight per day (mg/kg-day) was based on the male reproductive endpoint of decreased cauda epididymis weight in male F344/N rats. This effect on the male reproductive system was observed in a 13-week drinking water study (National Toxicology Program [NTP], 1993), with a BMDL1SD (lower 95% confidence limit on a benchmark dose associated with a 1 standard deviation (SD) change from the control mean) of 1.9 mg/kg-day.

In support of the IRIS entry, a comprehensive review and summary of the available toxicological data and the Agency’s evaluation were published as a Toxicological Review (U.S. EPA, 2010b). The U.S. EPA documents (2010a and 2010b) satisfy the formal identification and sufficiency of evidence criteria in the Proposition 65 regulations.

For more information and the full notice please refer to the link above.