OSHA 30 Hour Construction Program Practice Test

In tunnels and underground areas, how long should smoke be allowed to clear after blasting?

1. 10 minutes

2. 15 minutes

3. 20 minutes

4. 30 minutes

The correct answer is: 15 minutes

In tunnel and underground work environments, it is crucial to allow sufficient time for smoke to clear after blasting to ensure the safety of personnel and the effectiveness of emergency response measures. The correct response indicates that 15 minutes should be allowed for smoke to dissipate before re-entering the area after a blasting operation. This timeframe is established to minimize hazards associated with reduced visibility and inhalation of potentially harmful gases or particulate matter released during the blast. Time allowances are based on safety standards and best practices that acknowledge the dynamics of smoke dispersion in confined spaces like tunnels. Allowing for this specified time not only enhances visibility but also decreases the risk of respiratory issues among workers and improves overall safety conditions. Clearing the area appropriately before resuming work ensures that those entering the space can do so under conditions that are considerably safer.