Carcinogens Program


A carcinogen is a substance or agent capable of causing cancer. They are chronic toxicants with long latency periods that can increase the risk of certain forms of cancer after repeated or prolonged exposures; however, they often do not have immediately noticeable health effects.


The California Occupational Safety and Health Administration (Cal/OSHA) §5209 (and other sections) requires that no worker be exposed to carcinogen concentrations above established limits.


Anyone working with carcinogens must also review the following:

Carcinogen Safety: Quick Guide for PIs and Lab Supervisors

Carcinogen Training — Mandatory each year for all carcinogen users

Chemical Hygiene Plan

Control Banded Standard Operating Procedures

Formaldehyde Program Manual

For additional information go to: Known and Probable Human Carcinogens as described by the American Cancer Society.


Prior to working with any carcinogens, please consult with your EH&S Department Safety Advisor (DSA) or the UCSF Chemical Hygiene Officer to assess your level of exposure.

All carcinogens are regulated by Cal/OSHA and categorized under the three main categories listed below:

Listed – Listed are the most hazardous and more restrictive class of carcinogens. Cal/OSHA has established extensive regulations governing their distribution, handling, and use. Any handling or use of the 13 “listed” carcinogens below requires evaluation by EH&S before the material is ordered and reporting to Cal/OSHA.





Benzidine and its salts


3,3’-Dichlorobenzidine and its salts

bis-Chloromethyl Ether


Methyl Chloromethyl Ether





Regulated — If work with any of these carcinogens leads to exposure levels above certain limits, Cal/OSHA requires additional safety precautions, exposure monitoring, and medical surveillance for those performing this work. The specific limits vary depending on the specific carcinogen. "Regulated carcinogens" is an extensive list - common examples found in UCSF laboratories include methylene chloride/dichloromethane, benzene, and formaldehyde. All work with carcinogens must be accompanied with a Standard Operating Procedure (SOP) and proper lab-specific training provided or arranged by the Principal Investigator (PI).

Select — Select carcinogens are defined as “known to be carcinogenic” by the National Toxicology Program or classified as "carcinogenic to humans" or "reasonably anticipated to be carcinogens" by the International Agency for Research on Cancer. This is the broadest of the three categories regulated by Cal/OSHA. Carcinogens are also categorized using the Globally Harmonized System (GHS) categories listed below. GHS is a worldwide initiative to promote standard criteria for classifying chemicals according to their health hazards, physical hazards, and environmental hazards.

Group 1: Carcinogenic to humans
Group 2A: Probably carcinogenic to humans
Group 2B: Possibly carcinogenic to humans

All work with carcinogens must be accompanied with a Standard Operating Procedure (SOP) and proper lab-specific training provided or arranged by the Principal Investigator (PI).

Carcinogen Use in Rodents

Researchers using any of the following chemicals must follow the SOP on “Particularly Hazardous Chemicals (PHC) in Rodents.”  Special handling procedures apply to these animals and their cages and bedding.



For questions regarding carcinogens at UCSF, please contact the Chemical Hygiene Officer at EH&S: (415) 476-1300

EHS Categories

Industrial Hygiene Public Health Biological Safety Chemical Safety Lab Safety Radiation Safety Hazardous Waste Fire and Life Safety