California Assembly Bill 455, authored by Assembly Member Liz Ortega, protects California home owners from exposure to tobacco smoke residue, known as thirdhand smoke. The bill, signed by Governor Newsom in October, 2025, went into effect on January 1, 2026.
The bill defines thirdhand smoke as the toxic chemical residue left behind by tobacco smoke.
SECTION 1. The Legislature finds and declares both of the following:
(a) “Thirdhand smoke” is the toxic chemical residue left behind by tobacco smoke. It accumulates in carpets, walls, and furniture, becomes embedded in building materials, and persists for years after smoking stops.
(b) Thirdhand smoke-polluted buildings expose occupants to more than 10 toxic chemicals listed in Proposition 65 (1986).
The bill requires the seller of single-family homes to disclose in writing their knowledge of residue from or history of smoking or vaping nicotine products on the property.
SECTION 3. Section 1102.6k is added to the Civil Code, to read:
1102.6k
(a) In addition to any other disclosure required pursuant to this article, it shall be the sole responsibility of a seller of a single-family residential property subject to this article who has actual knowledge of the existence of any residue from smoking tobacco or nicotine products, or any history of occupants smoking tobacco or nicotine products on the property, to disclose that knowledge to the buyer in writing.
(b) For the purposes of this section, the following apply: (1) ” Residue from smoking tobacco or nicotine products” means a chemical accumulation resulting from the smoking of tobacco or nicotine products, and may be indicated by the smell of tobacco smoke or by test results that indicate elevated levels of nicotine on surfaces or in dust. (2) “Smoking tobacco or nicotine products” includes the use of an electronic cigarette or vape device for inhaling an aerosol.
The bill updates the Residential Environmental Hazards Guide, which educates sellers and buyers about eight environmental hazards, to include thirdhand smoke.
SECTION 4. Section 25417.2 is added to the Health and Safety Code, to read:
25417.2.
(a) For purposes of this section, “thirdhand smoke” means the toxic chemical residue left behind by tobacco smoke.
(b) The Department of Toxic Substances Control shall update the Homeowners’ Guide to Environmental Hazards created pursuant to Section 10084.1 of the Business and Professions Code, updated pursuant to Sections 13261, 25417, and 25417.1, and as required to be updated pursuant to Section 10084.2 of the Business and Professions Code, to include a new section on thirdhand smoke, in accordance with both of the following:
(1) To offset the costs associated with updating the guide, the Department of Toxic Substances Control shall delegate the responsibility for the update to the Center for Tobacco and the Environment at San Diego State University, which shall use existing center personnel and research resources, to the extent those resources are available.
(2) The Department of Toxic Substances Control shall review the update proposed by the Center for Tobacco and the Environment at San Diego State University to ensure the update adequately educates and informs consumers on all of the following:
(A) Thirdhand smoke as a common environmental hazard that is located on, and affects, real property.
(B) The significance of thirdhand smoke as a common environmental hazard and what can be done to mitigate this hazard.
(C) Sources that can provide more information on thirdhand smoke as a common environmental hazard for the consumer.
