CDPH Lead Inspector/Assessor California State Practice Exam

How long after lead abatement should clearance sampling be performed?

1. 30 minutes

2. 1 hour

3. 2 hours

4. 4 hours

The correct answer is: 1 hour

Clearance sampling after lead abatement is a critical step to ensure that the area is free from lead contamination and is safe for occupancy. The appropriate timeframe to carry out clearance sampling is typically one hour after the completion of the abatement activities. This allows sufficient time for any airborne lead particles that may have been disturbed during the abatement process to settle, providing a more accurate assessment of the lead levels in the environment. Performing clearance sampling too soon, such as immediately after work or within 30 minutes, could yield misleading results due to the presence of settled dust or residue that has not yet had time to settle, potentially indicating higher lead levels than are actually present when the area is stable. Furthermore, waiting longer than one hour, such as 2 hours or 4 hours, could lead to changes in environmental conditions that may also affect lead levels, making it less reliable for immediate safety assessments in the context of post-abatement verification. Therefore, the one-hour timeline is a standard practice that balances accuracy with the need for timely results.