Hazard Communication (HazCom) and the Right To Know (RTK)

Under the California Labor Code and the California Occupational Safety and Health Act, all employers in California are legally obligated to establish a hazard communication program. This program emphasizes workplace safety and requires employers to inform their employees of the hazardous substances to which they are exposed at the job site.

The requirements for developing, implementing, and maintaining a hazard communication program are found in Title 8 of the California Code of Regulations (T8 CCR), Section 5194. Subsection 5194(b)(6) contains the Safe Drinking Water and Toxic Enforcement Act (Proposition 65), which was added to the original hazard communication regulation in 1991. The UCSC HazCom Policy has been designed to meet these requirements.


The California Hazard Communication Standard applies (except for the exemptions and exclusions listed below) to all California employers, regardless of size, whose employees may be exposed to hazardous substances. Employers are required to provide information to their employees about the hazardous substances to which they may be exposed, by means of a hazard communication program, labels and other forms of warning, material safety data sheets, and information and training.

All hazardous substances found in the workplace under normal conditions of use as well as in reasonably foreseeable emergency conditions (i.e., a spill or release) are covered by the standard. The rule of thumb commonly used is the "household quantities" or consumer products exemption criteria. If you are using a chemical product in the same quantity and frequency of use that you would at home, you do not need an SDS and hazcom training for it. However, that same product used in a way which would expose a person more than could reasonably be expected at home triggers the application of a hazcom requirement. For example, oven cleaner of the type you can buy for home use, used once a month by an employee to clean an oven in a workplace kitchen, would be considered exempt. If the same employee used that same product to clean an oven every day, the increased exposure would warrant hazcom training.

Exemptions and Exclusions

1. Chemicals in closed containers. Although operations in which employees handle hazardous substances only in sealed containers (e.g., warehouse, transportation, or retail sales) are exempt from the full standard, employers are still required to:

  • Ensure that labels on incoming containers are not removed or defaced.
  • Obtain and maintain Safety Data Sheets (SDSs) and make them readily accessible to employees in their work area(s) during each work shift.
  • Train employees so they know how to handle and protect themselves in the event of a chemical spill or a leak from a sealed container. 

2. Laboratories. Employees who engage in the laboratory use of hazardous chemicals are exempt from the hazard communication regulation if they meet all of the following conditions:

  • Chemical manipulations are carried out on a “laboratory scale” — a single person using small quantities of hazardous chemicals in procedures that are not part of a production process, nor in any way simulate a production process; and
  • Multiple chemicals or chemical procedures are used; and
  • Protective laboratory practices and equipment are available and in common use industry-wide to minimize the potential for employee exposure to hazardous chemicals. 

These employees are, however, subject to T8 CCR, Section 5191, "Occupational Exposure to Hazardous Chemicals in Laboratories."

3. The following types of chemicals are excluded from the hazard communication regulation:

  • Hazardous wastes regulated by the EPA   
  • Tobacco products   
  • Natural wood or chemically untreated wood products for retail sale   
  • Manufactured items—articles that are handled/processed in a way that does not result in employee exposure via inhalation, ingestion, or skin absorption, such as items for immediate use or retail sale   
  • Food, drugs, and cosmetics consumed or used by the employees on the job site   
  • Retail trade establishments, except for processing and repair work areas   
  • Pesticide use regulated by the California Department of Food and Agriculture   
  • Consumer products, unless quantities used or exposures are greater than ordinary home consumer quantities or exposures 

Information Resources

OSHA FAQ about hazard communication

SDS information and sources