What Is California Proposition 65? A Complete Guide for Businesses (2026)

Introduction: Why Proposition 65 Matters

If your business sells products in California—or ships products online to California consumers—you must understand California Proposition 65 (Prop 65).

Prop 65 is one of the most actively enforced chemical compliance regulations in the United States. Many businesses assume it only requires adding a warning label. In reality, it is a comprehensive compliance framework involving product evaluation, chemical risk assessment, documentation, and ongoing monitoring.

What Is California Proposition 65?

California Proposition 65 requires businesses to:

• Identify exposures to chemicals known to cause cancer, birth defects, or reproductive harm
• Evaluate whether exposure levels exceed established safe thresholds
• Provide clear warnings when required
• Maintain documentation supporting compliance decisions

The regulation is administered by the California Office of Environmental Health Hazard Assessment (OEHHA), which maintains a list of over 900 regulated chemicals and updates it regularly. :contentReference[oaicite:0]{index=0}

Who Needs to Comply with Prop 65?

Prop 65 applies to businesses that:

• Sell or distribute products in California
• Operate e-commerce stores shipping to California
• Manufacture products that may expose individuals to listed chemicals
• Have 10 or more employees

Even businesses located outside California must comply if their products are sold within the state.

What Triggers a Prop 65 Warning?

A warning is required when a product exposes consumers to a listed chemical above established safe harbor levels.

• NSRL (No Significant Risk Level) for carcinogens
• MADL (Maximum Allowable Dose Level) for reproductive toxins

If exposure exceeds these thresholds, a warning must be provided. If not, businesses must maintain documentation demonstrating why a warning is not required.

Common Chemicals Under Proposition 65

• Lead
• Cadmium
• Arsenic
• Acrylamide

These chemicals can be found in dietary supplements, food products (such as chocolate and matcha), cosmetics, and packaging materials.

Understanding Prop 65 Warning Requirements

Warnings must be:

• Clear and reasonable
• Provided prior to exposure
• Properly formatted with a warning symbol
• Displayed on labels, websites, or retail listings

Example Warning:

⚠️ WARNING: This product can expose you to chemicals including lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm.

Prop 65 Compliance Is a System—Not Just a Label

A common mistake is treating Prop 65 as a labeling requirement. In reality, compliance requires a structured system:

• Product and ingredient evaluation
• Laboratory testing (ISO 17025 accredited)
• Exposure assessment calculations
• Supplier documentation review
• Compliance determination
• Ongoing regulatory monitoring

Without these elements, compliance may not be defensible if challenged.

Required Compliance Documentation

• Applicability assessments
• Product and chemical review checklists
• Chemical list reference registers
• Safe harbor level references (NSRL and MADL)
• Laboratory testing reports
• Supplier disclosures and certifications
• Exposure assessment documentation
• Compliance determination records
• Warning justification files

Why Businesses Fail Prop 65 Compliance

• Lack of proper or updated testing
• Over-reliance on supplier information
• Missing exposure assessments
• Incomplete documentation
• Incorrect or missing warnings
• Failure to monitor regulatory updates

Prop 65 enforcement is active and often driven by private enforcement actions, making proactive compliance essential.

Industries Most Affected

• Dietary supplements
• Food and beverage products
• Cosmetics and personal care
• Packaging and food-contact materials
• Amazon and e-commerce sellers

Final Thoughts

California Proposition 65 is often misunderstood. It is not just about adding a warning label or conducting a single test—it requires a complete, documented compliance system.

Key Question:

Can your business prove compliance if challenged?

Get Started

If you are unsure about your current Prop 65 compliance status, taking a proactive approach is critical. Establishing structured documentation, testing protocols, and monitoring systems helps protect your business and support long-term compliance.