The lack of consistent requirements for testing and remediating toxins in smoke, like lead and asbestos, which can settle into walls and ducts during a wildfire, have left residents in fear that moving back to their homes could make them sick. ↧ When is it safe to return home after a wildfire? California becomes... Houses that survive fires can be contaminated with poisons from smoke like lead and asbestos. But there have been no consistent rules for testing or remediation.