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Providing Early Warning About Workplace Hazards

Background and Purpose

In 1977, exposure to the pesticide dibromochloropropane (DBCP) caused a group of workers in California to become sterile.  Studies published 18 years earlier had shown that DBCP caused similar reproductive damage in animals.  In response to this unfortunate incident, the California Legislature created the Hazard Evaluation System and Information Service (HESIS) to identify workplace hazards and to provide “early warnings” to California workers and employers.  Since 1979, HESIS has warned of cancer and reproductive damage caused by chemicals used in the dry cleaning, semiconductor, and hospital industries, and by several widely used industrial solvents.

HESIS identifies and evaluates new and unappreciated workplace chemical hazards, alerts workers and employers when new hazard information becomes available, and recommends protective occupational health standards for the hazards to Cal/OSHA.


  • Conduct ongoing review of scientific literature, governmental reports, industry studies, and medical case reports to identify new and unappreciated health hazards;
  • Evaluate the health hazard information and determine if California workers are at risk for illness or disease;
  • Develop health hazard alerts and advisories with input from key stakeholders;
  • Identify trade associations, unions, and other governmental agencies that can assist in distributing the alerts and advisories;
  • Issue alerts and advisories to affected workers and employers.


Related Health Information
Program Information
Last modified on: 2/10/2017 11:23 AM