California Proposition 65 Testing FAQ

The Proposition 65 list contains approximately 900 chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. The list is updated regularly as new substances are evaluated.

Some commonly tested chemicals include:

• Lead
• Cadmium
• Arsenic
• Mercury
• Phthalates
• Diethanolamine (DEA)

These chemicals may be found in a wide variety of materials and products, including metals, plastics, paints, coatings, electronics, cosmetics, food products, and consumer goods.

Not every product needs to be tested for every chemical. The substances of concern depend largely on the product’s materials, manufacturing process, and planned use.

A Proposition 65 warning may be required if a product exposes California consumers to a listed chemical above the applicable safe harbor level.

Products commonly associated with Proposition 65 warnings include:

• Electronics
• Jewelry
• Furniture
• Cookware
• Cosmetics
• Food and dietary supplements
• Vinyl and plastic products
• Hardware and tools

However, the law applies to virtually any consumer product sold in California if exposure exceeds the allowable limits. Testing helps determine whether a warning is necessary or whether exposure falls below regulatory thresholds.

Safe harbor levels are daily exposure limits established by California’s Office of Environmental Health Hazard Assessment (OEHHA). If exposure remains below these levels, a Proposition 65 warning is generally not required.

There are two primary types of safe harbor levels:

• No Significant Risk Level (NSRL): This is the daily exposure level of a chemical linked to cancer that is generally considered to result in no more than one excess case of cancer in 100,000 people exposed over a 70-year lifetime.
• Maximum Allowable Dose Level (MADL): This is the highest daily amount of a chemical, associated with causing birth defects or reproductive harm, that is not expected to threaten human health even if someone is exposed to this amount every day.

Rather than measuring only how much of a chemical is present in a product, Proposition 65 focuses on how much a consumer is actually exposed to during normal use.

A warning label is not automatically required simply because a listed chemical is present. Many companies avoid warnings by demonstrating that consumer exposure remains below the applicable safe harbor level.

This may involve:

• Testing products to calculate daily exposure
• Reformulating products to reduce regulated chemicals
• Changing raw materials or suppliers
• Reviewing supplier documentation alongside laboratory testing

Testing allows manufacturers to reach informed compliance decisions while possibly avoiding unnecessary warning labels.

Proposition 65 does not specify a single required test method.

Instead, testing focuses on identifying the chemicals that may be present in a product and measuring them at levels sensitive enough to evaluate consumer exposure.

The process commonly begins by reviewing the product’s material composition to determine which listed chemicals are most likely present. Laboratories then perform targeted analytical testing based on the product’s materials and planned use.

This precise approach helps companies avoid unnecessary testing while providing the information needed to evaluate compliance.

The testing method depends on the specific chemical being analyzed.

Common analytical techniques include:

• ICP-MS or ICP-OES for heavy metals such as lead, cadmium, arsenic, and mercury
• GC-MS or LC-MS/MS for phthalates and many organic compounds

After laboratory testing is complete, results can be used to estimate consumer exposure and compare those values to California’s safe harbor limits.

Because Proposition 65 exposure thresholds are often extremely low, testing frequently requires parts-per-billion sensitivity.

Supplier information is useful, but it does not always replace testing.

Material formulations, technical data sheets, and supplier declarations can help identify which Proposition 65 chemicals may be relevant and narrow the scope of testing.

However, supplier documentation may not verify actual chemical concentrations or demonstrate that consumer exposure falls below California’s safe harbor limits.

Laboratory testing is often the most reliable way to confirm compliance and support regulatory documentation.

Failing to comply with Proposition 65 can lead to costly legal action.

The law is enforced by the California Attorney General, local government agencies, and private individuals or organizations. Most cases begin with a 60-Day Notice of Violation.

Possible consequences include:

• Civil penalties of up to $2,500 per violation, per day
• Payment of the plaintiff’s attorneys’ fees
• Product reformulation, warning label changes, or removal from the California market

Because Proposition 65 also applies to imported products and products sold online in California, testing can help businesses reduce the possibility of costly penalties and compliance issues.