California Prop 65 Compliance Guide for Businesses

California Proposition 65 compliance is a major requirement for companies that sell products in California. For manufacturers, importers, distributors, retailers, marketplace sellers, and brand owners, the challenge is not only knowing whether a warning label is needed. The real challenge is managing chemical data, supplier evidence, exposure assessments, product documentation, online warnings, and regulatory changes across many products and sales channels.

Prop 65, officially known as the Safe Drinking Water and Toxic Enforcement Act of 1986, requires businesses to inform Californians about exposures to chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. It also protects California drinking water sources from contamination by listed chemicals.

For companies selling consumer products, electronics, furniture, textiles, tools, packaging, cosmetics, food-related products, automotive parts, industrial components, or private-label products into California, Prop 65 should be treated as an ongoing product compliance program, not a one-time label review.

N-Methyl-N-formylhydrazine

OEHHA added N-Methyl-N-formylhydrazine to the Prop 65 list as a carcinogen effective December 8, 2025. The warning requirement for significant exposures takes effect on December 8, 2026.

Companies should monitor whether this chemical is relevant to their products, materials, byproducts, or supplier data.

Vinyl acetate

Vinyl acetate was added to the Prop 65 list as a carcinogen effective January 3, 2025. OEHHA states that the warning requirement for significant exposures to vinyl acetate takes effect on January 3, 2026.

Businesses should review whether vinyl acetate is relevant to their materials, adhesives, coatings, polymers, manufacturing inputs, or supplier documentation.

Bisphenol S, also known as BPS

OEHHA added the male reproductive toxicity endpoint for BPS effective January 3, 2025, and later added the developmental toxicity endpoint effective December 8, 2025.

This is important for companies reviewing plastics, coatings, resins, thermal papers, and other bisphenol-related material systems.

What Is California Prop 65?

California Proposition 65 is a right-to-know law. It requires businesses to provide a clear and reasonable warning before exposing individuals in California to listed chemicals that may cause cancer or reproductive harm. The official Prop 65 chemical list is maintained by California’s Office of Environmental Health Hazard Assessment, known as OEHHA.

The law can apply even if a company is not physically located in California. The California Attorney General explains that out-of-state manufacturers of retail products are not exempt when their products cause exposures to individuals in California.

This means Prop 65 is relevant for global manufacturers, importers, distributors, e-commerce sellers, marketplace sellers, and brands that sell or ship products into the California market.

Does Prop 65 Apply to My Business?

Prop 65 may apply if your business sells, distributes, imports, manufactures, or offers products for sale in California and those products may expose users to a listed chemical.

A business should review Prop 65 applicability when it sells products through:

Prop 65 is especially important for companies with large product portfolios, multiple suppliers, frequent material changes, or limited visibility into product composition.

Latest California Prop 65 Updates Businesses Should Know

OEHHA’s 2025 warning amendments are one of the most important recent Prop 65 changes. The amendments make short-form warnings more informative, clarify warning methods for products sold online and through catalogs, confirm short-form warnings may be used for food products, and add tailored safe harbor warnings for certain motor vehicle and marine vessel parts.

OEHHA also provides a three-year transition period for businesses currently relying on older short-form warnings, plus an unlimited sell-through period for products manufactured and labeled with existing short-form warnings before or during the transition period.

What Changed with Short-Form Prop 65 Warnings?

The short-form warning has been widely used because it is compact and easier to place on small labels or packaging. The updated rules make the short-form warning more specific by requiring more informative content, including at least one listed chemical name in the warning.

This matters because many companies previously used broad warning language without identifying a specific chemical. Under the updated framework, businesses should review whether their existing warning templates, label artwork, packaging files, website warnings, and marketplace listings remain aligned with the new safe harbor warning requirements.

For companies managing many SKUs, this creates a practical compliance challenge: the warning must match the product, the listed chemical, the exposure endpoint, and the sales channel.

What Changed for Online and Catalog Sales?

Prop 65 compliance is not limited to the physical product label. OEHHA’s updated warning rules clarify safe harbor warning methods for products sold on the internet and in catalogs.

For e-commerce and marketplace sales, businesses should check whether warnings are clearly visible before purchase and properly associated with the product. A warning that appears only in a general website footer, terms page, or hidden compliance page may not be enough.

For catalog sales, the warning should be connected clearly to the product being purchased. This is important for companies selling through printed catalogs, digital catalogs, distributor platforms, online stores, and third-party marketplaces.

How Do I Know If My Product Needs a Prop 65 Warning?

This is the main question most businesses ask.

A product may need a Prop 65 warning if it causes an exposure to a listed chemical above the applicable safe harbor level, where one exists. Prop 65 is exposure-based, which means the presence of a listed chemical in a product does not automatically decide the answer. The key question is whether the product causes an exposure that requires a warning.

OEHHA explains that safe harbor levels include No Significant Risk Levels, known as NSRLs, for cancer-causing chemicals and Maximum Allowable Dose Levels, known as MADLs, for chemicals causing reproductive toxicity. Exposures below safe harbor levels are exempt from Prop 65 warning requirements.

A practical decision process usually looks like this:

This is why Prop 65 compliance should not be handled only by copying a warning label. Businesses need a documented basis for warning or not warning.

What Chemicals Are Covered by Prop 65?

The Prop 65 list contains a wide range of naturally occurring and synthetic chemicals known to the State of California to cause cancer, reproductive harm, or both. OEHHA explains that listed chemicals may include ingredients or additives in pesticides, household products, food, drugs, dyes, or solvents, and may also be used in manufacturing and construction or created as byproducts of chemical processes.

The current Prop 65 list is available from OEHHA in online, PDF, Excel, and CSV formats. OEHHA notes that the Excel version includes the listing mechanism for each chemical and safe harbor level where one has been adopted.

For businesses, this means the chemical-list review should be structured and repeatable. A one-time search is not enough, because new chemicals can be added and existing listings can be updated.

Recent Chemical-List Updates to Monitor

p,p′-bisphenol chemicals

OEHHA selected p,p′-bisphenol chemicals for review by the Developmental and Reproductive Toxicant Identification Committee for possible listing under Prop 65 as reproductive toxicants. OEHHA also held a June 18, 2026 meeting that included discussion and updates on hazard identification materials for p,p′-bisphenol chemicals.

This is a useful reminder that companies should monitor chemicals under review, not only chemicals already listed.

Proposed NSRLs for 1-bromopropane and diethanolamine

OEHHA proposed Prop 65 No Significant Risk Levels for 1-bromopropane and dermal exposure to diethanolamine. In June 2026, OEHHA posted modifications and extended the public comment deadline to July 2, 2026.

This matters because safe harbor levels can directly affect exposure decisions and warning strategy.

Prop 65 Compliance by Product Category

Different product categories face different Prop 65 questions. The examples below are not automatic violations, but they show where companies often need chemical screening, supplier follow-up, testing, or exposure review.

The important point is that Prop 65 risk depends on the product, chemical, exposure route, use scenario, and available safe harbor level.

What Evidence Should Businesses Keep for Prop 65 Compliance?

Businesses should keep records that support their Prop 65 decisions. This is especially important if a product receives a 60-day notice, if a customer asks for evidence, or if internal teams need to understand why a product carries a warning.

Useful Prop 65 documentation may include:

This documentation should be linked to the correct SKU, product version, supplier, material, and sales channel.

What Happens If a Business Does Nothing?

Ignoring Prop 65 can create legal, commercial, and reputational risk. The California Attorney General explains that Prop 65 may be enforced through civil lawsuits by the Attorney General, district attorneys, certain city attorneys, and private parties acting in the public interest after providing at least 60 days’ notice of an alleged violation.

Civil penalties can be significant, and enforcement often creates additional business disruption, including legal costs, settlement discussions, product relabeling, customer questions, supplier investigations, and marketplace corrections.

The business risk is not only the penalty. It is also the lack of traceable evidence when a company cannot quickly explain its Prop 65 decision.

Common Prop 65 Compliance Mistakes

Treating Prop 65 as only a label issue

A warning may be required, but a warning alone is not a complete compliance system. Businesses also need chemical screening, supplier data, exposure review, documentation, and change control.

Assuming chemical presence automatically means warning

Prop 65 is exposure-based. A listed chemical may be present, but the compliance decision depends on whether the product causes an exposure above the relevant level.

Assuming chemical absence without supplier evidence

Many companies rely on incomplete supplier statements. A strong Prop 65 process requires evidence that is current, product-specific, supplier-specific, and linked to the correct material or component.

Forgetting online and catalog warnings

The updated warning rules clarify requirements for internet and catalog sales. Companies should not review only the physical label while ignoring product pages, marketplace content, and digital catalogs.

Not monitoring chemical-list changes

The Prop 65 list changes over time. Businesses should monitor new listings, endpoint changes, proposed safe harbor levels, and chemicals under review.

Using spreadsheets without version control

Spreadsheets may work for a small number of products, but they become risky when companies manage many SKUs, suppliers, materials, warning templates, and sales channels.

Practical California Prop 65 Compliance Checklist

Use this checklist to evaluate readiness:

Why Manual Prop 65 Compliance Is Risky

Manual Prop 65 management often depends on scattered spreadsheets, supplier emails, disconnected test reports, static label files, and individual employee knowledge. This creates several risks:

Product data may not be linked to the correct supplier or component.

Warning decisions may not show which chemical, exposure route, or safe harbor level was considered.

Online warnings may not match physical labels.

Supplier declarations may become outdated.

New chemical listings may not be applied to existing products.

Teams may not know which products need review after a material, supplier, or regulation changes.

For companies selling hundreds or thousands of products, this can make Prop 65 compliance difficult to scale and difficult to defend.

How ComplyMarket Helps with California Prop 65 Compliance

ComplyMarket helps businesses manage Prop 65 as a structured product compliance workflow rather than a manual labeling task. ComplyMarket’s Prop 65 compliance service supports applicability and exposure mapping, BOM screening against the official Prop 65 list, data gap analysis, testing plans, exposure assessment, documented threshold approaches using NSRLs and MADLs where available, warning implementation, monitoring, and change-control procedures.

For manufacturers, importers, distributors, retailers, and brand owners, ComplyMarket can help centralize the evidence needed to make and defend Prop 65 decisions. This includes supplier declarations, material data, test reports, exposure assessments, warning decisions, label versions, and online warning records.

ComplyMarket’s product compliance software is designed to help companies manage regulations, track evidence, and ensure market readiness in one platform.

ComplyMarket can support Prop 65 compliance by helping teams

This gives compliance teams stronger visibility, better traceability, and a more scalable process for California market access.