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By Deepa Shetty | Wed Dec 31 2025 | 2 min read

Table of Contents

For OEMs and contract manufacturers, Proposition 65 compliance sits in a gray zone — and that’s exactly where risk accumulates.

OEMs design products but often lack direct control over materials. Contract manufacturers build products but rarely own compliance decisions.

Yet under Proposition 65, liability does not disappear just because responsibility is shared.

When enforcement occurs, regulators do not care how work was divided. They care whether listed chemicals were present — and whether the business had reasonably ascertainable knowledge.

Why OEMs & Contract Manufacturers Face Unique Prop 65 Exposure

OEM–CM relationships introduce structural challenges:

  • split ownership of design, materials, and sourcing
  • limited visibility into sub-tier suppliers
  • reliance on contractual assurances instead of data
  • rapid design iterations and SKU variants
  • private-label and white-label production

These factors create gaps where Prop 65 risk can hide — even when both parties believe compliance is “covered.”

Who Is Responsible Under Proposition 65?

Proposition 65 assigns responsibility broadly to:

  • manufacturers
  • importers
  • distributors
  • retailers

In practice, this means:

  • OEMs cannot fully outsource Prop 65 responsibility
  • contract manufacturers cannot assume OEMs will absorb liability

If a listed chemical is present and exposure occurs, both parties may be pulled into enforcement, regardless of contractual language.

Common Prop 65 Risk Sources in OEM–CM Supply Chains

In OEM and contract manufacturing models, Prop 65 exposure often enters through:

  • plastics, resins, and polymers selected by CMs
  • coatings, paints, and finishes applied during manufacturing
  • solders, alloys, and platings
  • cables, batteries, chargers, and power components
  • adhesives, inks, and processing aids

These materials are often chosen for performance or cost — not chemical transparency.

Why Contracts and Declarations Are Not Enough

OEMs often rely on:

  • compliance clauses in manufacturing agreements
  • supplier declarations from CMs
  • generic RoHS or REACH statements

Contract manufacturers rely on:

  • OEM specifications
  • “build-to-print” assumptions
  • limited disclosure obligations

These approaches fail because:

  • they lack material-level chemical data
  • they do not enforce change notifications
  • they do not demonstrate reasonably ascertainable knowledge

Under Prop 65 enforcement, contracts are not evidence of compliance.

BOM & Design Reuse Multiply Risk

OEMs and CMs frequently reuse:

  • reference designs
  • tooling
  • approved materials
  • sub-assemblies

Across:

  • multiple customers
  • private-label variants
  • regional product lines

If a listed chemical exists in one reused material, Prop 65 exposure can propagate silently across many products — owned by different brands.

Without BOM-centric tracking, this risk remains invisible.

What Regulators Expect in OEM–CM Models

In enforcement scenarios involving OEMs and contract manufacturers, regulators expect to see:

  • clarity on who controls material decisions
  • traceability between materials, components, and finished goods
  • reassessment when designs, materials, or suppliers change
  • consistent warning logic across similar products

Ambiguity between OEM and CM roles is not viewed as a defense.

How OEMs & Contract Manufacturers Manage Prop 65 Effectively

Successful OEM–CM compliance programs align on data, not assumptions.

They implement:

Material-Level Chemical Visibility

Tracking substances and CAS numbers at the material and component level.

Clear Compliance Ownership

Defining who collects, validates, and updates chemical data — regardless of who designs or builds.

Supplier & Change Enforcement

Requiring notification when materials, formulations, or sub-suppliers change.

BOM-Centric Risk Mapping

Understanding how shared designs and materials propagate Prop 65 exposure.

Audit-Ready Documentation

Maintaining evidence that shows how compliance decisions were made and updated.

This turns Prop 65 from a contractual dispute into a controlled process.

Prop 65 Is a Shared Risk — Not a Transferable One

OEMs cannot outsource Prop 65 liability. Contract manufacturers cannot ignore it.

For both parties, compliance depends on visibility, structure, and coordination — not paperwork.

Those that rely on contracts alone remain exposed, even when intentions are good.

A Smarter Way Forward

Acquis Compliance helps OEMs and contract manufacturers align around material-level visibility, BOM-centric risk tracking, and audit-ready documentation—so Prop 65 decisions stay consistent across shared designs, suppliers, and product variants.

It’s not about shifting liability. It’s about making compliance provable.

Speak to Our Compliance Experts


Prop 65 Compliance for OEMs & Contract Manufacturers

Who is responsible for Proposition 65 compliance — OEMs or contract manufacturers?

Why are OEM–CM supply chains high risk under Prop 65?

Are contracts enough to manage Prop 65 compliance between OEMs and CMs?

Which materials commonly trigger Prop 65 issues in OEM manufacturing models?

How does design and BOM reuse affect Prop 65 risk for OEMs?

What data is needed to manage Prop 65 in OEM–CM relationships?

How can OEMs and contract manufacturers reduce Prop 65 enforcement risk?