California Proposition 65 Product Compliance Guide for Manufacturers

California Proposition 65 requires businesses to address exposures to chemicals known to cause cancer, birth defects, or other reproductive harm. For manufacturers, compliance is not simply a labeling exercise. It requires understanding where relevant chemicals may occur in products, determining whether exposure can occur, evaluating applicable safe harbor levels, managing supplier information, and maintaining evidence that supports the compliance decision.

This guide explains how manufacturers can build a practical Proposition 65 compliance process across products, materials, suppliers, and supporting documentation.

What Is California Proposition 65?

California Proposition 65, formally the Safe Drinking Water and Toxic Enforcement Act of 1986, requires businesses to provide clear and reasonable warnings before knowingly and intentionally exposing people to listed chemicals, subject to applicable provisions and exemptions.

The program is administered by the California Office of Environmental Health Hazard Assessment (OEHHA). Manufacturers should therefore work from current regulatory information and the current Proposition 65 chemical list when assessing products.

For background on the agency and its role, see the Office of Environmental Health Hazard Assessment (OEHHA).

The Proposition 65 list is updated as chemicals are added or removed. A compliance process should therefore account for regulatory changes rather than treating a one-time product assessment as permanently valid.

For the broader collection of Regilient Proposition 65 resources, see the California Proposition 65 compliance topic hub.

What Does Proposition 65 Mean for Manufacturers?

For manufacturers selling products into California, the central compliance question is:

Could the product result in an exposure to a Proposition 65-listed chemical that requires a warning?

Answering that question can require information from multiple stages of the product and supply chain.

A practical assessment may involve:

1. Identifying relevant chemicals and materials
2. Mapping chemicals to product components
3. Collecting supplier and material information
4. Evaluating potential exposure pathways
5. Considering applicable safe harbor levels
6. Determining whether a warning is required
7. Applying the appropriate warning approach where necessary
8. Maintaining evidence supporting the decision
9. Reassessing products when materials, suppliers, formulations, or regulatory requirements change

The objective is not simply to determine whether a listed chemical exists somewhere in the product. The compliance assessment needs to consider whether the circumstances create a relevant exposure.

Step 1: Identify Proposition 65 Chemicals in Your Products

The first step is understanding whether materials or components used in a product contain chemicals that appear on the Proposition 65 list.

This can be difficult for manufacturers with complex bills of materials because information may be distributed across:

• Raw materials
• Components
• Subassemblies
• Coatings
• Adhesives
• Plastics
• Metals
• Electronics
• Cables
• Packaging
• Surface treatments
• Supplier declarations

A manufacturer should establish a traceable relationship between the product, its components, the relevant materials, and the evidence supplied by the supply chain.

This is particularly important when a product contains many components sourced from different suppliers.

For manufacturers dealing with complex bills of materials, see Proposition 65 compliance across complex BOMs.

Step 2: Collect Supplier and Material Data

Manufacturers often depend on suppliers for information about chemical composition, material content, and potential Proposition 65 relevance.

Supplier data can include:

• Material declarations
• Chemical disclosures
• Product composition information
• Compliance declarations
• Test reports
• Supporting technical documentation
• Information about changes to materials or formulations

A supplier declaration can support a compliance assessment, but it should be evaluated in the context of the manufacturer's own product and exposure assessment.

For electronics manufacturers, Proposition 65 supplier compliance provides additional guidance on supplier information.

Where supplier requirements need to be incorporated into the compliance process, see enforcing Proposition 65 requirements on suppliers.

Step 3: Evaluate Potential Exposure

The presence of a listed chemical does not by itself answer the Proposition 65 compliance question.

Manufacturers need to consider whether people can be exposed to the chemical through the intended or reasonably foreseeable use of the product.

Potential exposure considerations can include:

• How the product is used
• Who uses or handles it
• How frequently it is used
• Which parts of the product are accessible
• Whether a chemical can migrate, leach, transfer, or otherwise become available for exposure
• Whether manufacturing, installation, servicing, or other activities create relevant exposure pathways

The assessment should be supported by appropriate technical evidence rather than relying solely on the presence or absence of a chemical declaration.

For a more detailed discussion of exposure determination, see Proposition 65 exposure requirements for manufacturers.

For electronics-specific exposure considerations, see Proposition 65 electronics exposure rules.

Step 4: Check Applicable Safe Harbor Levels

California Proposition 65 provides safe harbor levels for certain listed chemicals.

Where an applicable safe harbor level exists, manufacturers can use the relevant level as part of their compliance assessment. Safe harbor information should be checked against the current regulatory requirements and the specific chemical and exposure scenario being evaluated.

Safe harbor levels should not be treated as a universal threshold for every Proposition 65 assessment because not every listed chemical has a safe harbor level.

See Proposition 65 safe harbor levels for more detail.

Step 5: Determine Whether a Proposition 65 Warning Is Required

The warning decision should follow from the manufacturer's assessment of the product, chemical, exposure pathway, and applicable requirements.

A manufacturer should be able to explain:

• Which Proposition 65-listed chemical is relevant
• Where the chemical occurs
• Which product or component is affected
• What exposure pathway was considered
• What evidence supports the assessment
• Whether an applicable safe harbor level was considered
• Why a warning is or is not required

This creates a defensible decision path instead of treating Proposition 65 as a simple chemical-presence check.

For a focused decision framework, see how to determine whether a Proposition 65 warning is required.

Step 6: Manage Warning Requirements

Where a warning is required, manufacturers need to ensure that the warning approach used for the product meets the applicable Proposition 65 requirements.

Warning requirements can depend on the product, sales channel, circumstances of exposure, and applicable warning provisions.

Manufacturers should therefore avoid treating a single warning format as appropriate for every product.

For electronics manufacturers, see Proposition 65 warning label requirements for electronics.

A separate resource is also available for understanding Proposition 65 warning labels.

Proposition 65 Compliance for Electronics Manufacturers

Electronics manufacturers face particular challenges because products can contain many components and materials supplied through multiple tiers.

A single product may contain:

• Printed circuit boards
• Cables and connectors
• Plastics
• Metal components
• Batteries
• Displays
• Coatings
• Adhesives
• Soldering materials
• Packaging materials

The compliance process therefore needs to connect component-level information to the finished product and its potential exposure scenarios.

See Proposition 65 compliance for electronics manufacturers for an electronics-specific implementation perspective.

Proposition 65 Compliance for OEMs and Contract Manufacturers

OEMs and contract manufacturers may operate across complex supply chains where responsibility for material information is distributed among multiple parties.

A practical process should establish:

• What information suppliers must provide
• How declarations are collected
• How submitted information is reviewed
• How gaps are escalated
• How product-level assessments are documented
• How changes to materials or components trigger reassessment

This is especially important where the same component is used across multiple products or supplied by different manufacturers.

See Proposition 65 compliance for OEMs and contract manufacturers for the specific supply-chain considerations.

Build a Repeatable Proposition 65 Compliance Workflow

A manufacturer should avoid treating Proposition 65 as a one-time certification exercise.

A repeatable workflow can follow this sequence:

Product → BOM → Components → Materials → Supplier data → Chemical identification → Exposure assessment → Safe harbor assessment → Warning decision → Evidence → Ongoing monitoring

1. Map the product

Identify the products and components that require assessment.

2. Identify relevant materials

Determine which materials and components may contain Proposition 65-listed chemicals.

3. Collect evidence

Gather supplier declarations, material information, testing data, and other supporting documentation.

4. Assess exposure

Evaluate how relevant chemicals could result in exposure during applicable product use or handling scenarios.

5. Evaluate safe harbor information

Where applicable, compare the relevant exposure assessment against the appropriate safe harbor information.

6. Make and document the decision

Record whether a warning is required and the evidence supporting that determination.

7. Monitor changes

Reassess when regulations, chemical listings, suppliers, materials, formulations, components, or product designs change.

What Evidence Should Manufacturers Maintain?

A defensible Proposition 65 compliance process should maintain evidence that allows the manufacturer to reconstruct how a compliance decision was reached.

Depending on the product and assessment, this may include:

• Product and BOM information
• Component information
• Supplier declarations
• Material disclosures
• Chemical information
• Test reports
• Exposure assessments
• Safe harbor references
• Warning determinations
• Supporting correspondence
• Review and approval records
• Change history

The important principle is traceability.

A manufacturer should be able to move from a compliance decision back to the product, component, material, supplier information, and evidence supporting that decision.

Common Proposition 65 Compliance Challenges

Incomplete supplier information

Suppliers may provide incomplete or inconsistent chemical information, making product-level assessment difficult.

Complex bills of materials

Large products can contain hundreds or thousands of components, making manual review difficult to maintain.

Changing regulations

The Proposition 65 list and related requirements can change over time, creating a need for ongoing monitoring.

Unclear exposure pathways

The presence of a listed chemical does not automatically establish the relevant exposure scenario. Manufacturers need to evaluate the circumstances surrounding the product.

Fragmented compliance evidence

When supplier declarations, testing records, BOMs, and compliance decisions are stored separately, it becomes harder to demonstrate how the final determination was made.

How Regilient Supports Proposition 65 Compliance

Regilient helps manufacturers organize product, material, supplier, and regulatory information into a more connected compliance workflow.

The platform can support activities such as:

• BOM screening
• Supplier declaration collection and validation
• Material and chemical data management
• Compliance status mapping
• Exemption and regulatory assessment workflows
• Audit-ready compliance documentation
• Ongoing supplier engagement

The value of this approach is not simply automating a warning decision. It is creating a traceable process from product and supplier data through compliance assessment and supporting evidence.

Proposition 65 Compliance Checklist

Before completing a product assessment, manufacturers should be able to answer:

• Have relevant Proposition 65-listed chemicals been identified?
• Have affected products and components been mapped?
• Has supplier and material information been collected?
• Have potential exposure pathways been evaluated?
• Have applicable safe harbor levels been considered?
• Has the warning requirement been assessed?
• Is the decision supported by documented evidence?
• Can the assessment be traced back to the relevant product and supplier information?
• Is there a process for monitoring changes to the Proposition 65 list?
• Will supplier, material, or product changes trigger reassessment?

If several of these questions cannot be answered confidently, the compliance process may have an evidence or data gap.

Download the Proposition 65 Compliance Guide

For a practical reference that can be used when reviewing your compliance process, download the California Proposition 65 Compliance Guide.

Frequently Asked Questions

What is Proposition 65 compliance for manufacturers?

Proposition 65 compliance requires manufacturers to evaluate whether their products may result in exposures to listed chemicals and determine what action is required under the applicable requirements.

Does the presence of a Proposition 65-listed chemical automatically require a warning?

Not necessarily. The presence of a listed chemical is an important part of the assessment, but the compliance determination also depends on the applicable exposure circumstances and other relevant provisions.

Do manufacturers need supplier declarations?

Supplier declarations can provide important information for product-level assessments, particularly where manufacturers do not have direct visibility into the chemical composition of every component. They should form part of a broader evidence and assessment process.

How often should Proposition 65 compliance be reviewed?

Manufacturers should establish a review process that accounts for changes to Proposition 65 requirements, chemical listings, suppliers, materials, components, product designs, and other factors that could affect the original assessment.

How can manufacturers manage Proposition 65 compliance across complex BOMs?

The process should connect BOM and component information with material, chemical, supplier, exposure, and evidence data. This makes it easier to identify affected products and maintain traceability when information changes.

Does Proposition 65 apply only to electronics?

No. Proposition 65 can affect products and businesses across many industries. Electronics are one area where complex BOMs and supply chains can make compliance particularly challenging.

Conclusion

Proposition 65 compliance is fundamentally a product, supply-chain, exposure, and evidence management problem.

Manufacturers need more than a list of chemicals or a generic warning policy. They need a repeatable process that connects product and BOM data with supplier information, chemical identification, exposure assessment, applicable safe harbor information, warning decisions, and supporting evidence.

The strongest compliance process is one that can answer not only whether a product requires action, but also why, based on what evidence, and what changed since the assessment was completed.

Explore the Proposition 65 compliance resources to continue into the specialized guidance for exposure, warnings, electronics, suppliers, BOMs, and other implementation areas.