California Prop 65 and Heavy Metals in Glass Bottles and Decoration

Prop 65 is a warning obligation, not a product ban. A bottle does not fail Prop 65 because it contains a listed chemical; it creates a duty to warn unless exposure is below the applicable safe-harbour level. Most confusion in this category comes from suppliers selling "Prop 65 certificates" that do not exist.

Close-up of the decorated coloured coating surface of a glass bottle under bright light

What the law actually requires

Formal name: Safe Drinking Water and Toxic Enforcement Act of 1986.
Administered by California's Office of Environmental Health Hazard Assessment, which maintains the listed-chemicals catalogue and safe-harbour levels.
Lead and cadmium are both listed, which is why they dominate glass-decoration testing.
The duty to warn sits with the business causing the exposure, normally the brand owner or importer.

Where the risk sits in a spirits bottle

Container glass — standard soda-lime container glass is normally lead-free, so the wall itself is low risk.
Crystal and lead glass — a genuine source of lead exposure.
Enamels, pigments and decals — the most common source, particularly on the outside of the bottle.
Coatings and sprays — can carry heavy metals depending on pigment system.
Closure liners and capsules — usually low risk but worth including in the test scope.

The exposure pathway that matters is contact with the mouth or the liquid, so the rim and any decorated area near the finish deserve particular attention.

What testing looks like

An extraction or release test using a food simulant, run for a defined time and temperature.
Analysis typically by ICP-MS or atomic absorption.
The laboratory should hold ISO 17025 accreditation, and the report should name the method.
The result is then compared with the safe-harbour level for the listed chemical.

Safe-harbour levels are updated over time, so always check the current figure rather than reusing an old threshold.

What to ask a supplier for

A heavy metal release test report for the decorated bottle, naming the method and accredited laboratory.
Confirmation of which surfaces were tested, including the rim if the decoration reaches it.
Confirmation that the coating or ink supplier holds its own food-contact declaration of compliance.
Batch traceability linking the report to the production run you are buying.

Common supplier claims to treat carefully

"Prop 65 compliant" without test data — compliance is not a property you can assert; it is a conclusion from testing.
"Lead-free glass" applied to decorated bottles — the glass may be lead-free while the enamel is not.
Old test reports — formulations change, so require reporting per batch or per production period.
Certificate templates — there is no official Prop 65 certificate to issue.

The importer's position

Responsibility sits with the operator placing the product on the California market. In practice that is the importer or brand owner. Obtain documentation before shipping, not after a customs hold or a retailer query.

Why "Prop 65 certificates" do not exist

Prop 65 is administered by the California Office of Environmental Health Hazard Assessment. OEHHA does not certify products, approve suppliers, or issue compliance documents. There is no Prop 65 certificate, and a supplier who offers one is either reselling a test report or misunderstanding the law.

What does exist is evidence: a test report showing that exposure to a listed chemical is below the applicable safe-harbour level, or a reasoned exposure assessment. Either is defensible; a certificate is not.

The two ways to comply

Show exposure is below the safe-harbour level — then no warning is required.
Provide a clear and reasonable warning — then the warning obligation is met.

Both are legitimate. Which is cheaper depends entirely on the test result, which is why testing comes first.

Where risk concentrates in a spirits bottle

Ranked by exposure pathway:

The rim and finish — contacts the mouth directly. Historically the issue was lead and cadmium release from decorated rims on ceramic and glass ware, which is why rim-area testing exists.
The closure liner and any internal coating — direct liquid contact.
External decoration — lower exposure path, but screened routinely.

Plain undecorated flint or amber glass sits at the low end of this list. Decoration moves a bottle up it.

What to put in a supplier file

A defensible file is short:

Declaration of compliance identifying the material, the applicable regime and the contact conditions.
Test reports for heavy metals on decorated areas, with dates.
Liner specification and its food-contact declaration.
The drawing revision the reports relate to.

Update it whenever decoration or suppliers change, and keep the revision numbers aligned. Most compliance failures are document-control failures, not material failures.

Warning mechanics in practice

The warning must be clear and reasonable, which in practice means legible, permanently attached and positioned to be seen before purchase.
Responsibility sits with the party in the chain that creates the exposure, which for imported goods is typically the importer or the brand owner.
Safe-harbour levels are substance-specific and revised, so a threshold used on one programme may not be current on the next.

Confirm the current figure for the substance in question at the time of each programme rather than reusing an earlier one.

Working with suppliers on this

Ask for three things, in writing:

A statement of which listed substances the decorated article has been screened for.
The dated test reports, with the laboratory and method named.
Confirmation of which drawing revision and decoration specification the reports cover.

A supplier who can produce all three is straightforward to work with. One who offers a generic certificate is not, and that distinction is the useful output of the exercise.

Building the file into the programme

Prop 65 work is cheap when it is scheduled and expensive when it is reactive:

Screen at sample approval, alongside adhesion and abrasion testing.
Re-screen when decoration changes, including a change of colour or supplier.
Keep the reports with the drawing revision they relate to.
Confirm the current safe-harbour level at the start of each programme.

Treated this way, it is a checklist item. Left to the end, it is a launch risk.

Key takeaways

Prop 65 is a warning obligation, not a product ban, and there is no such thing as a Prop 65 certificate.
Comply either by showing exposure below the safe-harbour level or by giving a clear warning.
Risk concentrates at the rim and mouth-contact area, then the liner, then external decoration.
Safe-harbour levels are revised, so confirm the current figure for each programme.
Screen at sample approval alongside adhesion and abrasion testing.
Keep dated reports indexed to the drawing revision they cover.

Frequently Asked Questions

What is California Prop 65?

Prop 65 is the Safe Drinking Water and Toxic Enforcement Act of 1986. It requires businesses to give a clear warning before knowingly exposing people in California to listed chemicals, including lead and cadmium.

Does Prop 65 apply to glass bottles?

It applies to exposure from any product sold in California, and that includes heavy metals that could be released from glass or, more commonly, from decorated surfaces such as coatings, enamels and inks.

Is a Prop 65 certificate a real thing?

No. There is no government-issued Prop 65 certificate. What exists is test data showing whether exposure exceeds the applicable safe-harbour level, together with a supplier's declaration about the material composition. Anyone offering a Prop 65 certificate without test data is offering a piece of paper, not evidence.

Who gives the warning?

The business exposing people to the chemical, which is normally the brand owner or importer selling into California, not the overseas glass factory. The obligation travels with the party placing the product on the Californian market, so settle it contractually before the first shipment.

Does clear glass contain lead?

Soda-lime container glass is normally lead-free. Lead risk comes from crystal glass, some enamels, pigments and older decorated surfaces, which is why heavy metal release testing focuses on the decoration rather than the glass wall. Confirm the composition with the plant rather than assuming.

What test should I request?

Ask for a heavy metal release or extraction test on the decorated surface, and confirm the method and the laboratory's ISO 17025 accreditation. The report should name the surface tested, the extraction conditions and the detection limits, otherwise it cannot be compared with any limit.

Written by Eric Jiang, Glass Packaging Engineer, 12 years.

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