Revision to the Basis for Listing a Chemical: Chlorsulfuron

Proposition 65 provides mechanisms for administratively listing chemicals that are known to the State to cause cancer or reproductive toxicity (Health and Safety Code section 25249.8(b)).  A chemical may be listed under Proposition 65 when a body considered to be authoritative has formally identified the chemical as causing cancer or reproductive toxicity.  The criteria for listing chemicals through the authoritative bodies mechanism are set forth in Title 27, California Code of Regulations, section 25306.

The Office of Environmental Health Hazard Assessment (OEHHA), within the California Environmental Protection Agency, is the lead agency for the implementation of Proposition 65.  OEHHA listed chlorsulfuron, as identified in the table below, as known to the State to cause reproductive toxicity via the authoritative bodies listing mechanism effective May 14, 1999.  Developmental, male reproductive, and female reproductive toxicity were all identified as endpoints forming the basis for listing.

The listing was based on findings by the U.S. Environmental Protection Agency (U.S. EPA), a Proposition 65 authoritative body.  U.S. EPA (1994a and 1994b) concluded that: “…there is sufficient evidence for listing chlorsulfuron on EPCRA section 313 pursuant to EPCRA section 313(d)(2)(B) based on the available developmental and reproductive toxicity data for this chemical.”

The developmental toxicity finding was based on increased incidence of fetal resorptions in rabbits.  The reproductive toxicity finding was based on a decreased fertility index in a rat multi-generation reproduction study.

Because U.S. EPA identified reproductive toxicity on the basis of a decrease in fertility index in a multi-generation reproduction study, which could potentially have resulted from adverse reproductive effects in both males and females, OEHHA identified both male and female reproductive toxicity as bases for listing chlorsulfuron under Proposition 65.   A more recent document from U.S. EPA clarified that the agency interpreted the data from that study as demonstrating only decreased female fertility (U.S. EPA, 2002).   There is therefore no formal identification of male reproductive toxicity for chlorsulfuron by U.S. EPA.  Consequently, effective June 11, 2010, OEHHA will remove male reproductive toxicity as a basis for the listing of chlorsulfuron.   Chlorsulfuron will remain on the Proposition 65 list based on U.S. EPA’s findings of developmental and female reproductive toxicity.

Chemical Reference

• Chlorsulfuron

Related Notices

• Chemical Listed Effective May 14, 1999 as Known to the State to Cause Reproductive Toxicity: Chlorsulfuron

  May 14, 1999

Footnotes and References

U.S. Environmental Protection Agency (U.S. EPA, 1993).  Support Document for the Addition of Chemicals from Federal Insecticide, Fungicide, Rodenticide Act (FIFRA) Active Ingredients to EPCRA Section 313.  US EPA/OPP.

U.S. Environmental Protection Agency (U.S. EPA, 1994a).  Proposed Rule: Addition of Certain Chemicals; Toxic Chemical Release Reporting; Community Right to Know.  Federal Register 59: 1788.

U.S. Environmental Protection Agency (U.S. EPA, 1994b).  Final Rule: Addition of Certain Chemicals; Toxic Chemical Release Reporting; Community Right to Know.  Federal Register 59(229): 61432.

U.S. Environmental Protection Agency (U.S. EPA, 2002).  Chlorsulfuron: Toxicology Disciplinary Chapter for the Registration Eligibility Decision (RED).  Health Effects Division, Office of Pesticide Programs.  PC Code: 118601.