EU Compliance 6 min read
California Prop 65 Warning Requirements for Workplaces
California Health and Safety Code §25249.6 requires a clear and reasonable warning before a business knowingly and intentionally exposes anyone to a listed chemical. This guide explains the workplace provisions in 27 CCR §§25605 and 25600.2, including warning content, timing, exposure thresholds and compliance evidence relevant to 2026 enforcement.
California Prop 65 Warning Requirements for Workplaces
California Prop 65 warning requirements begin with Health and Safety Code §25249.6. It binds a person in the course of doing business where that person knowingly and intentionally exposes another individual to a chemical listed by the California Office of Environmental Health Hazard Assessment (OEHHA), unless the exposure is below the applicable safe-harbor level. The corresponding occupational provisions are in Title 27, California Code of Regulations (27 CCR) §25605, with the general warning rules in §§25600.2 and 25601.
The 2026 enforcement focus makes the distinction between a warning obligation and a product-label preference important. A label is not automatically sufficient for a workplace exposure, and a workplace sign does not necessarily satisfy every consumer-product or environmental warning duty.
The legal trigger and the parties covered
Section 25249.6 prohibits the exposure unless the responsible business gives a clear and reasonable warning or proves that the exposure falls within the statutory exemption. “Person in the course of doing business” is broad enough to cover manufacturers, importers, distributors, employers, retailers, contractors and other commercial operators, not only the company that formulated the chemical-containing product.
The duty concerns exposure, not simply the presence of a listed substance. A company therefore needs an exposure assessment for relevant operations, products and foreseeable use. The assessment should identify the chemical, route of exposure, exposed population, frequency, duration and the evidence supporting the calculated dose.
A business can also rely on the Proposition 65 safe-harbor levels where the exposure remains at or below the applicable level. For carcinogens, the relevant benchmark is the no significant risk level (NSRL). For reproductive or developmental toxicants, it is the maximum allowable dose level (MADL). These levels are published in 27 CCR Article 7, including §§25701 and 25703, and may be expressed as a daily intake or an air concentration.
Occupational warnings under 27 CCR §25605
Section 25605 provides the specific route for occupational exposures. A business may use a warning that meets §25600.2 and may deliver it by one of the transmission methods allowed by §25601. The warning must reach the exposed person before or at the time of exposure; a document supplied after the work has been completed is not an effective warning.
Section 25605 also permits compliance through the applicable California Occupational Safety and Health Act requirements, including the hazard communication requirements in 8 CCR §5194. This does not remove the need for an effective hazard communication programme. Safety data sheets (SDSs), container labels, employee training and workplace signs must be consistent with the actual chemical hazards and the Proposition 65 exposure determination.
For Prop 65 warning labels for workplace areas, the practical issue is coverage. A sign at an entrance may be appropriate where every person entering the controlled area receives the warning, but it is weak evidence where employees, contractors or visitors can bypass the sign or enter through another route. The employer should retain the sign wording, location, installation date, inspection records and training material.
Required warning content and presentation
The safe-harbor wording is set out in 27 CCR §25602. The warning normally uses the yellow triangular warning symbol, the word “WARNING:” in bold type, the applicable hazard statement and the OEHHA website address. The standard short wording is:
- “WARNING: Cancer - www.P65Warnings.ca.gov.”
- “WARNING: Reproductive Harm - www.P65Warnings.ca.gov.”
- “WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov.”
A business must select the statement that matches the listed chemical exposure. It should not use a cancer-only statement when the relevant listed chemical creates a reproductive or developmental exposure, and it should not rely on a generic “chemical exposure” message where the safe-harbor text is required.
Under §25602, the warning must be conspicuous and readable. It must be placed so that a person can see it before exposure, or at the time exposure begins where that is the permitted delivery point. The warning must also be in a language understood by the intended audience when the business uses a translated warning as part of its communication system; the official safe-harbor wording and website address should not be altered casually.
The full warning may identify one or more chemicals. The short-form option is subject to the conditions in §25602, including the required symbol and type-size rules. Product packaging, websites, catalogues and workplace communications should therefore be reviewed separately rather than treated as interchangeable.
Exposure limits, listed chemicals and technical records
A warning analysis must use the current OEHHA Proposition 65 list. The list is maintained under 27 CCR §27001 and related listing provisions, and it changes when chemicals are added, removed or reclassified. The California Prop 65 chemical list update 2026 should be checked against the company’s chemical inventory, formulations, SDS library and supplier declarations; a previous review is not evidence that the current inventory remains unchanged.
Where a business claims that no warning is required because exposure is below an NSRL or MADL, the file should show the numerical value used and the calculation method. Relevant evidence may include industrial hygiene sampling, validated emission data, exposure modelling, task-based air monitoring, dermal or ingestion assumptions and the uncertainty factors applied.
The safe-harbor levels are not universal workplace limits. A California Division of Occupational Safety and Health permissible exposure limit (PEL), an OSHA permissible exposure limit or an ACGIH threshold limit value may help assess occupational risk, but it does not automatically establish compliance with Proposition 65. The Prop 65 analysis must address the applicable NSRL or MADL, where one exists, and the actual exposure scenario.
When OEHHA adds a chemical, the effective date and any transition period matter. Businesses should record the list version reviewed, the date of the review, the listing date, the chemical’s endpoint and the date on which warning controls were implemented. A supplier’s “Prop 65 compliant” statement is useful support, but it does not replace the importer’s or employer’s own responsibility under §25249.6.
Evidence expected during enforcement
California enforcement can be initiated by the Attorney General, certain local prosecutors or private plaintiffs. Under §25249.7, a civil penalty can reach $2,500 per day for each violation. A private action normally follows the 60-day notice procedure in §25249.7(d), so incomplete records can become a material defence problem even where warnings were displayed.
For Prop 65 warning requirements for manufacturers, the evidence package should connect the product or process to the warning decision. At minimum, retain:
- The applicable OEHHA list version and chemical identification.
- The exposure assessment, including assumptions, units and calculation date.
- The NSRL or MADL used, or the reason no safe-harbor value applies.
- Approved label, sign, SDS and training text, with revision control.
- Distribution, installation and training records showing when and where the warning was delivered.
- Supplier declarations, laboratory reports and industrial hygiene data supporting the conclusion.
Records should distinguish California-facing controls from controls used in other states or countries. A warning designed for a consumer product may not show that employees received the occupational warning before exposure, while an SDS alone may not demonstrate the conspicuous communication required by §25605.
Takeaway: treat the warning as an exposure control
California Prop 65 warning requirements are satisfied by more than printing a symbol. The defensible position is one in which §25249.6 supplies the legal trigger, §25605 covers the occupational delivery route, §25600.2 supplies compliant content, and the exposure file demonstrates either a timely warning or a documented NSRL/MADL determination.
For 2026, the control system should be tied to OEHHA list surveillance and change management. Review new chemicals, reformulations, contractor activities and workplace layouts together; then preserve the evidence that proves the warning reached the people exposed.
Key facts
Machine-readable statements extracted from the sources above. Each fact keeps the same identifier across all six language versions.
HSC §25249.6
California Health and Safety Code §25249.6 prohibits knowingly and intentionally exposing another person to a listed chemical without a clear and reasonable warning, unless an exemption applies.
Fact ID:
warning_obligation27 CCR §25605
Section 25605 governs occupational exposure warnings and requires delivery before or at the time of exposure.
Fact ID:
occupational_clause$2,500 per day
Health and Safety Code §25249.7 authorizes a civil penalty of up to $2,500 per day for each violation.
Fact ID:
penalty_limit60 days
A private Proposition 65 plaintiff generally must provide the notice required by HSC §25249.7(d) at least 60 days before filing an action.
Fact ID:
private_notice_periodNSRL and MADL
The safe-harbor framework uses a no significant risk level for carcinogens and a maximum allowable dose level for reproductive or developmental toxicants.
Fact ID:
safe_harbor_endpoints
Frequently asked questions
Does a workplace sign always satisfy California Prop 65?
No. Under 27 CCR §25605, the warning must reach the exposed person before or at the time of exposure. A sign may work where it is conspicuous and unavoidable, but an SDS or entrance sign alone may be inadequate for a different exposure route or access point.
What exposure level avoids a Prop 65 warning?
The business may rely on the applicable safe-harbor level where exposure is at or below the relevant no significant risk level for carcinogens or maximum allowable dose level for reproductive or developmental toxicants. The calculation and supporting evidence should be retained.
Are OSHA or Cal/OSHA limits the same as Prop 65 limits?
No. OSHA or Cal/OSHA exposure limits may support an occupational assessment, but they do not automatically establish compliance with Proposition 65. The analysis must address the Prop 65 listing and any applicable NSRL or MADL.
