Proposition 65

Acrylamide is a chemical listed under Proposition 65 as a carcinogen. It was first listed on January 1, 1990, under the ‘State’s Qualified Experts’ mechanism. Acrylamide forms naturally in starchy foods (e.g., potato chips, french fries, bread, coffee) when cooked at high temperatures through the Maillard reaction. OEHHA has established a No Significant Risk Level (NSRL) of 0.2 micrograms per day for acrylamide. Proposition 65 has been the subject of significant litigation over acrylamide in food products, including a landmark First Amendment lawsuit by the California Chamber of Commerce challenging mandatory cancer warnings on coffee and other foods containing acrylamide.

An Additional Settlement Payment (ASP) is a payment made by a defendant in a Proposition 65 enforcement action above and beyond civil penalties, typically directed to a non-governmental third-party organisation (such as an environmental or public health group) rather than to OEHHA. ASPs became controversial because private enforcers could direct these payments to affiliated organisations they controlled or chose. California Attorney General regulations (Title 11, CCR, Chapter 4) significantly restrict ASPs: ASPs must not exceed 75% of the civil penalties in the settlement, must have a sufficient nexus to the underlying litigation and benefit California residents, and must be subject to judicial approval in court judgments.

The California Attorney General (AG) is the primary government enforcement authority for Proposition 65 under Health & Safety Code §25249.7. The AG has authority to file civil enforcement actions for Proposition 65 violations, review and comment on private enforcement settlements and judgments, and collect 75% of all civil penalties assessed. The AG’s office publishes annual summaries of Proposition 65 settlements and judgments. The AG also maintains regulations governing private party enforcement (Title 11, CCR, Chapter 4). In 2024, the AG’s office recorded over 1,300 Proposition 65 settlements totalling tens of millions of dollars.

Biomonitoring refers to the measurement of the body burden of a chemical in biological media (blood, urine, tissue, breast milk) to assess actual human exposure levels. In the Proposition 65 context, OEHHA uses biomonitoring data when available to estimate actual exposure levels and derive safe harbor thresholds. Under California’s Biomonitoring Program (SB 1379), OEHHA and the California Department of Public Health conduct population-level biomonitoring studies. Biomonitoring data can be relevant evidence in Proposition 65 enforcement litigation when demonstrating that actual exposure to a listed chemical is below the NSRL or MADL.

Bisphenol A (BPA) is a chemical listed under Proposition 65 as a reproductive toxicant (female endpoint) effective May 11, 2015, and separately listed as a reproductive toxicant (developmental endpoint) effective April 6, 2018. OEHHA has established a Maximum Allowable Dose Level (MADL) for BPA of 3 micrograms per day (female reproductive endpoint). BPA is widely used as a monomer in polycarbonate plastics and epoxy resins, appearing in food can linings, water bottles, thermal paper, and medical devices. BPA’s listing led to widespread reformulation of consumer products and significant enforcement litigation.

Bisphenol S (BPS) is an analogue of bisphenol A used as a BPA substitute in plastics, thermal papers, and personal care products. On January 28, 2025, California’s Developmental and Reproductive Toxicant Identification Committee (DARTIC) voted 9 to 0 to list Bisphenol S as a reproductive toxicant (male reproductive endpoint) under Proposition 65. Following the DARTIC vote, OEHHA proceeds to formally add the chemical to the Proposition 65 list, typically within approximately one year of the committee vote. Once listed, a warning would be required for exposures above the applicable Maximum Allowable Dose Level (MADL), which OEHHA has not yet established for BPS as of April 2026.

The California Code of Regulations (CCR) contains the implementing regulations for Proposition 65 in Title 27 (Environmental Protection), Division 4 (Safe Drinking Water and Toxic Enforcement Act of 1986), Chapter 6 (Clear and Reasonable Warnings), Sections 25600–25900. These regulations define: the criteria for a ‘clear and reasonable warning’ (Article 6); safe harbor warnings for consumer products (Articles 6 and 6.1); safe harbor warnings for specific exposure scenarios (e.g., food, dietary supplements, passenger vehicle parts, recreational marine vessel parts under new §§25607.50–25607.53, effective January 1, 2025); listing mechanisms (Article 3); and safe harbour levels (Article 7). Title 11 CCR Chapter 4 governs private enforcement reporting requirements.

A carcinogen under Proposition 65 is a chemical that is ‘known to the state to cause cancer.’ Chemicals are added to the Proposition 65 list as carcinogens through four mechanisms: (1) formal identification by the state’s Carcinogen Identification Committee (CIC) of OEHHA’s Scientific Advisory Panel; (2) required listing of chemicals identified by an authoritative body (such as IARC, US EPA, NTP, FDA) as causing cancer; (3) formal identification under California’s Labor Code (occupational carcinogens); or (4) chemicals identified in regulations as causing cancer via other state or federal processes. The No Significant Risk Level (NSRL) is the relevant safe harbour threshold for carcinogens. Vinyl acetate was added as a carcinogen effective January 3, 2025.

The Carcinogen Identification Committee (CIC) is the state’s qualified experts body within OEHHA’s Scientific Advisory Panel responsible for identifying chemicals as known to cause cancer for purposes of Proposition 65 listing. The CIC evaluates scientific evidence on carcinogenicity and can vote to list chemicals as carcinogens when the evidence clearly shows cancer causation in humans or animals. The CIC can also review chemicals for potential delisting. In December 2025, OEHHA referred ethoprop to the CIC for review for possible delisting from the Proposition 65 carcinogen list.

A Certificate of Merit is a mandatory pre-filing requirement for private enforcers bringing Proposition 65 warning violation enforcement actions. Under Health & Safety Code §25249.7(d), a private enforcer must include with their 60-Day Notice of Violation a certificate stating that they have consulted with a person with relevant expertise who has reviewed facts, studies, or other data regarding the alleged exposure, and that based on this review there is a reasonable and meritorious case for bringing a Proposition 65 action. The factual information supporting the certificate must also be provided to the California Attorney General. Courts may sanction frivolous enforcement actions where the certificate is deemed insufficient.

The maximum civil penalty under Proposition 65 is  $2,500 per violation per day for knowing and intentional violations of the warning or discharge prohibition provisions (Health & Safety Code §25249.7(b)). Courts consider multiple factors in determining the appropriate penalty amount, including: the nature and extent of the violation; the number of violations; the economic benefit gained by the violator; the deterrent effect; and the presence of any good faith efforts to comply. Private enforcers retain 25% of any civil penalties recovered; 75% is paid to OEHHA. In practice, civil penalties in private enforcement settlements are often much lower than the maximum, with attorney’s fees and costs constituting the largest component of most settlements.

A ‘clear and reasonable warning’ is the standard of warning required by Proposition 65 (Health & Safety Code §25249.6) when a business exposes any individual to a listed chemical above the applicable safe harbour level. A warning meets this standard when it is: (a) clear — provided in a manner that clearly communicates to each individual a message that the product or location contains a listed chemical and the nature of the health risk; and (b) reasonable — provided by a method reasonably calculated to reach the individual before exposure to the listed chemical. OEHHA’s Title 27 CCR regulations provide safe harbour warnings (both long-form and short-form) that, if followed exactly, are deemed to satisfy the clear and reasonable warning standard.

The Developmental and Reproductive Toxicant Identification Committee (DARTIC) is the state’s qualified experts body within OEHHA’s Scientific Advisory Panel responsible for identifying chemicals as known to cause birth defects, developmental toxicity, or other reproductive harm for purposes of Proposition 65 listing. DARTIC evaluates scientific evidence on reproductive and developmental toxicity. On January 28, 2025, DARTIC voted 9 to 0 to list Bisphenol S (BPS) as a reproductive toxicant (male reproductive endpoint) under Proposition 65. DARTIC also reviews chemicals for the MADL (Maximum Allowable Dose Level) determination process.

In addition to its warning requirements, Proposition 65 contains a separate prohibition under Health & Safety Code §25249.5 against the knowing discharge or release of a listed chemical into any source of drinking water or into water or onto land where it will pass into drinking water. This discharge prohibition applies to businesses with 10 or more employees. The discharge prohibition is distinct from the warning requirement and applies regardless of whether the quantity of chemical discharged causes a ‘significant risk’ as defined under the warning provisions. The threshold is whether the discharge creates a ‘significant risk’ of exposure to the population served by the drinking water source.

A Proposition 65 enforcement action is a civil lawsuit filed in California Superior Court alleging that a business has violated the warning or discharge prohibition provisions of the Act. Enforcement actions may be brought by: (1) the California Attorney General; (2) district attorneys; (3) city attorneys of cities with populations over 750,000; or (4) private persons or organisations acting in the public interest (‘private enforcers’). A private enforcer must first provide a 60-Day Notice of Violation to the alleged violator, the AG, and applicable district or city attorney. If no government enforcer initiates action within 60 days of the notice, the private enforcer may file suit. In 2024, there were over 1,300 Proposition 65 settlements, totaling tens of millions of dollars.

An exposure assessment is the quantitative or qualitative evaluation of the actual amount of a listed chemical that an individual is exposed to from a specific product, facility, or activity. Under Proposition 65, a warning is required only when exposure exceeds the applicable safe harbour level (NSRL for carcinogens; MADL for reproductive toxicants). OEHHA provides guidance on calculating exposure levels, including its ‘Proposition 65 Exposure Calculator,’ and technical guidance documents specifying default exposure assumptions (e.g., body weight, inhalation rates, dermal absorption factors, ingestion rates). Businesses may use product-specific exposure data to demonstrate that exposures do not require warnings.

A food safe harbour warning is a specific Proposition 65 safe harbour warning format for foods that expose consumers to listed chemicals above safe harbour levels. OEHHA’s December 2024 amendments (effective January 1, 2025) added a new short-form food warning option under Title 27 CCR §25607.53. For food products, the long-form warning has historically been required; the new short-form food warning option must include the name of at least one listed chemical. For cancer risk: ‘Consuming this product can expose you to [chemical name], a chemical known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov/food.’ Similar format applies for reproductive toxicants.

A government enforcer under Proposition 65 is a state or local government authority authorised to bring enforcement actions for Proposition 65 violations. Government enforcers include: the California Attorney General (with primary authority); district attorneys of any California county; and city attorneys of cities with populations exceeding 750,000 (currently Los Angeles, San Diego, San Jose, and San Francisco). If a government enforcer initiates a Proposition 65 action within 60 days of receiving a 60-Day Notice of Violation from a private party, the private party is preempted from filing their own suit. Government enforcement actions are generally considered more credible and complex than private enforcement actions.

An Interpretive Guideline is an official statement issued by OEHHA that interprets Proposition 65 regulations as applied to specific factual scenarios, without creating new legal obligations. Interpretive Guidelines clarify how existing law applies and are available to any person or business seeking guidance. They are distinct from Safe Use Determinations (SUDs), which are issued in response to specific factual requests and can be relied upon as a defence to a subsequent enforcement action. Interpretive Guidelines are published on the OEHHA website and may address product categories, exposure scenarios, or warning format questions.

‘Known to the state’ is the standard under Proposition 65 (Health & Safety Code §25249.8) for chemicals that have been officially listed as causing cancer or reproductive harm. A chemical is ‘known to the state’ to cause cancer or reproductive toxicity when OEHHA has officially listed it on the Proposition 65 chemical list through one of the approved listing mechanisms (CIC/DARTIC determination, authoritative body listing, Labor Code listing, or regulatory listing). This specific legal phrase distinguishes chemicals that trigger Proposition 65 obligations from chemicals that are merely suspected of causing harm. Once a chemical is ‘known to the state,’ the warning and discharge prohibitions apply.

Lead (Pb) is one of the most frequently cited chemicals in Proposition 65 enforcement. Lead is listed as both a carcinogen (listed October 1, 1992) and a reproductive toxicant (listed February 27, 1987). OEHHA has established a Maximum Allowable Dose Level (MADL) for lead of 0.5 micrograms per day (reproductive toxicity). For cancer risk, a No Significant Risk Level of 15 micrograms per day applies. Lead is found in a wide range of consumer products including electronics, jewellery, ceramics, plumbing fixtures, toys, and food contact materials. Lead-in-jewellery and lead-in-consumer-electronics cases represent some of the most common Proposition 65 enforcement actions.

A listing mechanism is one of four approved processes through which OEHHA adds chemicals to the Proposition 65 list as known to cause cancer or reproductive toxicity. The four mechanisms are: (1) the Formally Required Mechanism (chemicals identified by an authoritative body such as IARC, NTP, US EPA, or FDA as causing cancer or reproductive harm); (2) the State’s Qualified Experts mechanism (CIC or DARTIC determination based on scientific evidence review); (3) the Labor Code Mechanism (chemicals listed as occupational carcinogens under the California Labor Code); and (4) the Regulations/Administrative Action Mechanism (chemicals listed through specified state or federal regulatory processes). Each mechanism has distinct criteria, procedures, and timelines.

A long-form warning is the primary safe harbour warning format under Proposition 65 regulations (Title 27 CCR §25603 and §25607 et seq.), providing consumers with detailed information about their exposure to a listed chemical. For consumer products, the long-form warning must include: the Prop 65 warning symbol (yellow triangle with black exclamation mark); the signal word ‘WARNING:’ (or ‘CA WARNING:’ or ‘CALIFORNIA WARNING:’ per January 2025 amendments); at least one listed chemical name; and a reference to www.P65Warnings.ca.gov. For consumer products with carcinogen exposure: ‘WARNING: This product can expose you to [chemical name], which is known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov.’

A Maximum Allowable Dose Level (MADL) is the safe harbour level established by OEHHA for chemicals listed as reproductive toxicants under Proposition 65. Below the MADL, a business is not required to provide a Proposition 65 reproductive toxicant warning. The MADL is set at 1/1000 of the level shown to have no observable effect in the most sensitive reproductive endpoint study. Key MADLs include: lead: 0.5 μg/day; BPA: 3 μg/day; phthalates (DEHP): 8.7 μg/day; di-n-butyl phthalate (DBP): 8.7 μg/day; methanol: 47,000 μg/day. MADLs are published in Title 27 CCR §25805 and OEHHA’s Proposition 65 list (Excel version).

A tailored safe harbour warning for motor vehicle parts is a new warning format added by OEHHA’s December 2024 amendments (effective January 1, 2025), codified at Title 27 CCR §25607.50. This safe harbour warning applies to exposures that occur during the purchase, handling, or installation of parts for motor vehicles (cars, SUVs, vans, pickup trucks, motorcycles, ATVs). The required warning text is: ‘WARNING: Handling passenger or off-highway motor vehicle parts can expose you to chemicals such as phthalates and lead, which can cause cancer and reproductive harm. To minimize exposure, service the vehicle in a well-ventilated area, wear gloves, and wash your hands. For more information go to www.P65Warnings.ca.gov/motor-vehicle-parts.’

A No Significant Risk Level (NSRL) is the safe harbour exposure level established by OEHHA for chemicals listed as carcinogens under Proposition 65. Below the NSRL, a business is not required to provide a Proposition 65 cancer warning. The NSRL is set at the level of exposure that would cause no more than one excess case of cancer in 100,000 individuals exposed over a 70-year lifetime. Key NSRLs include: lead: 15 μg/day; acrylamide: 0.2 μg/day; arsenic: 10 nanograms/day; benzene: 12.7 μg/day; cadmium: 0.05 μg/day (tobacco); styrene: 27 μg/day. NSRLs are published in Title 27 CCR §25703 and OEHHA’s Proposition 65 list.

The Office of Environmental Health Hazard Assessment (OEHHA) is the primary California state agency responsible for implementing Proposition 65 (the Safe Drinking Water and Toxic Enforcement Act of 1986). OEHHA’s Proposition 65 responsibilities include: maintaining and updating the list of chemicals known to cause cancer or reproductive harm (900+ chemicals as of April 2026); establishing safe harbour levels (NSRLs and MADLs); developing and amending warning regulations (Title 27 CCR); issuing interpretive guidelines and Safe Use Determinations; supporting the Scientific Advisory Panel (including CIC and DARTIC); and receiving 75% of all civil penalties from Proposition 65 enforcement actions.

Proposition 65 warning regulations include specific requirements for products sold online and through catalogs. Under Title 27 CCR §25600.2(b), for an internet purchase, the Proposition 65 warning must be provided before the purchaser completes the purchase (i.e., before the transaction is finalised on the website). The warning must be clearly associated with the product listing. Under the January 2025 amendments, retailers must display a new short-form warning online within 60 calendar days after receiving notice of the new short-form warning from a manufacturer (for internet purchases made prior to January 1, 2028). Warnings delivered after purchase or at time of delivery do not qualify for safe harbour protection.

P65Warnings.ca.gov is the official California state website maintained by OEHHA that consumers and businesses are directed to in all Proposition 65 safe harbour warnings. This website provides: consumer information about specific chemicals and their health effects; product category fact sheets; business resources; the full Proposition 65 chemical list; frequently asked questions; and links to regulatory and enforcement information. All Proposition 65 safe harbour warning formats (long-form and short-form) must include a reference to www.P65Warnings.ca.gov or the relevant subcategory URL (e.g., www.P65Warnings.ca.gov/food, www.P65Warnings.ca.gov/motor-vehicle-parts).

Phthalates are a group of plasticiser chemicals listed under Proposition 65 as reproductive toxicants. Multiple phthalates are individually listed: Di(2-ethylhexyl) phthalate (DEHP) — listed as causing reproductive toxicity (male and female), MADL: 8.7 μg/day; Di-n-butyl phthalate (DBP) — listed, MADL: 8.7 μg/day; Diisodecyl phthalate (DIDP), Diisononyl phthalate (DINP), and others are also listed. Phthalates are commonly found in PVC plastic products, vinyl flooring, cables, medical devices, personal care products, and food packaging. Phthalates are specifically named in the new motor vehicle parts tailored warning (§25607.50) effective January 2025.

A private enforcer (sometimes called a ‘citizen enforcer’ or colloquially a ‘bounty hunter’) is a private individual or organisation who brings Proposition 65 enforcement actions ‘in the public interest’ under Health & Safety Code §25249.7. Private enforcers may bring suit if: (1) they have provided a 60-Day Notice of Violation to the alleged violator, the AG, and applicable district or city attorney; and (2) no government enforcer has filed suit within 60 days. Private enforcers who prevail receive 25% of assessed civil penalties plus attorney’s fees and costs. In 2024, there were over 1,300 Proposition 65 private enforcement settlements totalling tens of millions of dollars in payments to private enforcers and their attorneys.

Proposition 65 (formally the Safe Drinking Water and Toxic Enforcement Act of 1986) is a California voter initiative (Ballot Initiative, November 4, 1986) codified at California Health & Safety Code §25249.5 et seq. It requires: (1) businesses with 10 or more employees to provide a ‘clear and reasonable’ warning before knowingly exposing any person to a listed chemical above the safe harbour level; and (2) businesses to refrain from knowingly discharging listed chemicals into drinking water sources. As of April 2026, there are approximately 900 chemicals on the Proposition 65 list. The law is enforced by the California AG, district attorneys, city attorneys, and private enforcers. It applies to products sold or exposures occurring in California.

The Proposition 65 list is the official catalogue of chemicals ‘known to the state of California to cause cancer, birth defects or other reproductive harm’ maintained by OEHHA. As of April 2026, the list contains approximately 900 chemicals. OEHHA updates the list periodically — chemicals are added through the four listing mechanisms (CIC/DARTIC determination, authoritative body, Labor Code, regulatory listing). OEHHA publishes the list in PDF and Excel format on its website; the Excel version includes listing dates, safe harbour levels, and listing mechanism for each chemical. Businesses must screen their products and operations against the current Proposition 65 list.

A tailored safe harbour warning for recreational marine vessel parts is a new warning format added by OEHHA’s December 2024 amendments (effective January 1, 2025), codified at Title 27 CCR §25607.51. This applies to exposures during the purchase, handling, or installation of parts for recreational marine vessels (boats and other pleasure crafts not used for commercial purposes). The required warning text is: ‘WARNING: Handling recreational marine vessel parts can expose you to chemicals such as phthalates and lead, which can cause cancer and reproductive harm. To minimize exposure, service the vessel outdoors or in a well-ventilated area, wear gloves, and wash your hands. For more information go to www.P65Warnings.ca.gov/marine-vessel-parts.’

Reformulation is the process of changing a product’s composition to eliminate or reduce listed chemicals below Proposition 65 safe harbour thresholds, eliminating the need for a warning. Reformulation is one of two primary compliance strategies under Proposition 65 (the other being implementing a compliant warning). Successful reformulation requires: identification of the listed chemical(s) in the product; identification of suitable chemical substitutes that do not trigger other Proposition 65 listing or other regulatory obligations; testing to confirm that the reformulated product does not contain the listed chemical above safe harbour levels; and supply chain implementation to ensure reformulated materials are used consistently.

A retail seller under Proposition 65 regulations is a business that sells consumer products directly to end-use consumers in California. Under Title 27 CCR §25600.2(c), a retail seller is generally responsible for ensuring that required Proposition 65 warnings are transmitted to customers. Retail sellers may comply by: (1) affixing a Proposition 65 warning to the product; (2) posting point-of-sale notices; (3) using shelf tags; or (4) by relying on a manufacturer’s warning system under certain conditions. For online retail, the warning must appear on the product page before purchase. Retailers may be held independently liable for Proposition 65 violations if they sell products that require warnings but lack them.

A safe harbour level is the exposure threshold below which a Proposition 65 warning is not required. OEHHA establishes two types of safe harbour levels: the No Significant Risk Level (NSRL) for carcinogens — set at the exposure causing no more than one excess cancer case in 100,000 individuals over a 70-year lifetime; and the Maximum Allowable Dose Level (MADL) for reproductive toxicants — set at 1/1,000 of the level showing no observable reproductive effect. Safe harbour levels are optional — businesses may use their own risk assessments instead — but if a product’s exposure is below the safe harbour level, the business is exempt from the warning requirement for that chemical. As of April 2026, OEHHA has established specific NSRLs and MADLs for approximately 300 of the 900+ listed chemicals.

A safe harbour warning is a specific warning format defined in OEHHA’s Title 27 CCR regulations that, when used exactly as specified, provides a legal presumption that the warning meets the ‘clear and reasonable’ standard required by Proposition 65. Using a safe harbour warning eliminates the need to individually demonstrate that the warning method and content are adequate. OEHHA provides safe harbour warnings for: consumer products (long-form and new short-form with chemical name, effective January 1, 2025); food products; environmental exposures; occupational exposures; motor vehicle parts (new, effective January 1, 2025); recreational marine vessel parts (new, effective January 1, 2025); and other categories.

A Safe Use Determination (SUD) is a written statement issued by OEHHA, upon request from a business or trade group, that interprets and applies Proposition 65 regulations to specific facts submitted by the requestor. A SUD provides a formal OEHHA determination of whether a specific product, use, or exposure scenario complies with Proposition 65 or requires a warning. Unlike interpretive guidelines, a SUD can be relied upon as an affirmative defence in subsequent Proposition 65 enforcement actions — a business acting in good faith in accordance with an SUD is not subject to civil penalties for the conduct described in the SUD.

A short-form warning is an abbreviated Proposition 65 safe harbour warning format originally intended for small product packaging. OEHHA’s December 2024 amendments (finalized December 6, 2024, effective January 1, 2025) significantly updated the short-form warning requirements under Title 27 CCR §25603(d) and §25607.2. Key changes: (1) the short-form warning must now include the name of at least one listed chemical for each health risk endpoint (cancer and/or reproductive toxicity); (2) the warning can now be any size packaging (the previous small-package restriction has been removed); (3) the warning must use a 6-point font minimum and the Prop 65 warning symbol; (4) alternative signal words ‘CA WARNING’ or ‘CALIFORNIA WARNING’ are now permitted. A three-year transition period runs until January 1, 2028; products manufactured before that date with prior short-form warnings may continue to be sold.

A signal word is the bold, capitalised word that introduces a Proposition 65 warning. Under Title 27 CCR safe harbour warning regulations, the required signal word is ‘WARNING:’ The December 2024 amendments (effective January 1, 2025) added two alternative signal words that may also be used: ‘CA WARNING:’ and ‘CALIFORNIA WARNING:’ The addition of these alternatives allows businesses to indicate more clearly that the warning is specific to California law, which may help consumers and customers understand why a California-specific warning appears. The signal word must appear in all capital letters and bold print, and must be preceded by the Proposition 65 warning symbol.

A 60-Day Notice of Violation is the formal notice that a private enforcer must provide before filing a Proposition 65 enforcement action in court. Under Health & Safety Code §25249.7(d), the notice must: (1) be provided to the alleged violator, the California AG, and the applicable district or city attorney; (2) specify the alleged violation (what chemical, what product or exposure, what provision of law is violated); (3) include a Certificate of Merit; and (4) include factual information supporting the certificate of merit (provided to the AG). The 60-day period allows: government enforcers to initiate action (preempting the private suit); and the alleged violator to take corrective action, investigate the claim, and negotiate a resolution.

Proposition 65 applies only to businesses with 10 or more employees (Health & Safety Code §25249.11). Businesses with fewer than 10 employees are exempt from Proposition 65 warning requirements and the discharge prohibition. The number of employees is counted at the time of the alleged violation. For businesses near the 10-employee threshold, headcount includes full-time and part-time employees. Note: the small business exemption applies to the warning and discharge requirements but does not exempt small businesses from other California chemical regulations. Also, even exempt small businesses may face liability if their products are later resold by a covered business without compliant warnings.

Styrene is a synthetic chemical listed under Proposition 65 as a carcinogen (listed April 6, 2012). OEHHA has established a No Significant Risk Level (NSRL) for styrene of 27 micrograms per day. Styrene is used as a monomer in the production of polystyrene plastics, ABS plastic, rubber, and various resins. In the context of electronics and consumer products, styrene-containing plastics (polystyrene, ABS) are widely used for housings, packaging, and components. Food packaging using polystyrene may also trigger Proposition 65 concerns if styrene migrates into food above the NSRL.

A supplier declaration (also called a material declaration or substance declaration) in the Proposition 65 context is a written statement from a component or material supplier confirming the chemical content of supplied materials relative to Proposition 65-listed substances. Unlike EU RoHS (which has standardised material declaration requirements under EN IEC 63000:2018), Proposition 65 has no standardised mandatory declaration format. However, supplier declarations are a critical component of a manufacturer’s Proposition 65 compliance programme, providing the primary evidence base for determining whether products contain listed chemicals at exposure-triggering concentrations.

Tobacco smoke is identified as a source of Proposition 65-listed carcinogens and reproductive toxicants, including tobacco smoke (listed as a carcinogen October 1, 1988) and several specific tobacco smoke constituents (benzene, formaldehyde, vinyl chloride, cadmium, and others). Environmental tobacco smoke and ‘second-hand smoke’ are among the most common triggers for workplace, hotel, and building Proposition 65 exposure warnings. OEHHA has established specific safe harbour warnings for tobacco smoke-related exposures in the workplace and other environmental contexts.

Vinyl acetate is a chemical used as a monomer in the production of polyvinyl acetate (PVA) adhesives, polyvinyl alcohol, and ethylene-vinyl acetate (EVA) copolymers — materials widely used in adhesives, paints, paper coatings, and foam for footwear and sports equipment. Vinyl acetate was listed as a Proposition 65 carcinogen effective January 3, 2025, under the State’s Qualified Experts mechanism following a Carcinogen Identification Committee determination. As of April 2026, OEHHA has not yet established a specific No Significant Risk Level (NSRL) for vinyl acetate; in the interim, businesses must use OEHHA’s quantitative risk assessment methodology to determine whether their specific exposures create a ‘significant risk’ requiring a warning.

A Proposition 65 warning is the required notice that a business must provide to individuals before knowingly exposing them to a chemical listed as causing cancer or reproductive harm, when exposure exceeds the applicable safe harbour level (NSRL or MADL). The warning must be ‘clear and reasonable’ as defined in Health & Safety Code §25249.6 and Title 27 CCR §25600 et seq. Proposition 65 warnings may be provided through: product labels; shelf tags or signs at point of sale; on-site signage; catalog or internet website warnings; or direct notification (for workplaces and rental housing). OEHHA’s safe harbour warning regulations provide specific content, format, and transmission requirements that create a presumption of compliance.

The Proposition 65 warning symbol is the pictogram required in Proposition 65 safe harbour warnings: a black exclamation point in a yellow equilateral triangle with a black outline. This symbol is mandated by Title 27 CCR §25603 and must be included in all consumer product long-form and short-form safe harbour warnings, as well as in the new motor vehicle parts and recreational marine vessel parts tailored warnings (effective January 1, 2025). The symbol must be displayed at a size no smaller than the signal word and must be placed conspicuously on the product, label, or packaging. Digital uses of the symbol (websites, e-commerce) must also comply with conspicuousness requirements.

A workplace warning is a Proposition 65 safe harbour warning provided to employees who may be exposed to listed chemicals in their work environment. Under Title 27 CCR §§25606–25606.7, employers must provide Proposition 65 warnings for workplace exposures to listed chemicals above safe harbour levels. Workplace warnings may be provided through: employee notification (written notice, collective bargaining agreement, or training); posting of signs in the exposure area; including warning information in safety data sheets (SDS); or labelling of containers or equipment. Workplace warnings are distinct from consumer product warnings.