Overview
What is Thirdhand Smoke?
“Thirdhand smoke is the chemical residue that is left behind on clothes, skin, furniture, walls, and other surfaces after someone smokes.” – Thirdhand Smoke Resource Center
In homes, thirdhand smoke can be particularly difficult to remove because of its ability to absorb and embed into porous materials like drywall and stick to difficult-to-clean surfaces, like air ducts. Thirdhand smoke residue can stay in a home for years, exposing residents to tobacco smoke pollutants long after smoking ended. The residue is almost impossible to fully remove, and many people would not buy a home if they knew the previous owner smoked inside.
California’s Landmark Legislation Now Requires Disclosure of Thirdhand Smoke in Home Sales
In 2025, California signed Assembly Bill 455 into law and became the first state to require the disclosure of thirdhand smoke in residential real estate transactions.
The new law will go into effect in 2026, and serve three key functions:
- Define thirdhand smoke in California legislation for the first time.
- Require sellers to disclose knowledge of pasts smoking or vaping in their home to potential buyers in writing.
- Direct the Department of Toxic Substances Control to update the Residential Environmental Hazards Guide to include a new section on thirdhand smoke.
Click here to learn more.
The Policy Initiative (2023-2025)
This initiative began in 2023, at a time when the State of California did not require sellers to disclose the smoking history of a home to potential buyers. This left California buyers vulnerably to unknowingly purchasing homes polluted with thirdhand smoke.
The Policy Research Center conducted a review of California disclosure requirements to determine what was legally required to be disclosed during home sales and what education was provided to buyers. A previous study conducted in 2021 revealed that 96% of California residents want to know if a home they are about to buy is polluted with thirdhand smoke, but the attitudes of California professionals had not yet been studied. Researchers at the the Center surveyed California real estate agents and appraisers in order to learn what they knew about thirdhand smoke and other residential environmental hazards, and what they thought about requiring disclosure of thirdhand smoke.
Research Questions:
- What are the current disclosure requirements in California home sales regarding residential environmental hazards?
- What are real estate agents’ thoughts on thirdhand smoke disclosure?
- How do other stakeholders feel about disclosing thirdhand smoke?
- What makes a disclosure policy successful?
This initiative began in 2023, at a time when the State of California did not require sellers to disclose the smoking history of a home to potential buyers. This left California buyers vulnerably to unknowingly purchasing homes polluted with thirdhand smoke.
