California Proposition 65

Intrinsik’s scientific experts can offer advice for Proposition 65 (Prop 65).  Prop 65 is a California initiative intended to address concerns about exposure to toxic chemicals.

The State of California publishes a list of chemicals known to cause cancer or birth defects or other reproductive harm.  This list includes more than 900 chemicals.  Proposition 65 requires businesses to warn Californians about significant amounts of chemicals in the products they purchase.  Businesses are exempt from the warning requirement if the exposures they cause are so low as to create no significant risk of cancer or birth defects or other reproductive harm.

To assist businesses, the Office of Environmental Health Hazard Assessment (OEHHA) develops numerical guidance levels, known as “safe harbor numbers” for determining whether a warning is necessary or whether discharges of a chemical into drinking water sources are prohibited.  If there is no safe harbor level for a chemical, businesses that expose individuals to that chemical would be required to provide a Proposition 65 warning, unless the business can show that the anticipated exposure level will not pose a significant risk of cancer or reproductive harm.  A business has “safe harbor” from Proposition 65 warning requirements if exposure to a chemical occurs at or below the safe harbor levels.


  • Review product formulations to determine the presence of product constituents on the current list
  • Development of NSRL/MADL for chemicals with no OEHHA derived safe harbor number
  • Utilizing standard and accepted exposure and risk assessment methods, we can conduct risk assessments and Safe Use Determinations to assist with labelling decisions
  • We can assist with responses to plaintiff issued 60-day notices
  • We can provide expert advice in legal proceedings and in discussions and negotiations with plaintiffs, OEHHA and the Attorney General


How Can We Help?

Our scientists have the expertise to address your complex
toxicological health and environmental issues, including product
development and business risks to avoid scientific and regulatory delays.

Contact Us