What is a key requirement when closing manholes and valves after loading hazardous materials?

When closing manholes and valves after loading hazardous materials, it is essential that they must be tested for leaks. This step is crucial because any leaks can lead to significant hazards, including environmental contamination, exposure to dangerous materials, and potential injuries or fatalities. Testing for leaks ensures that all closures are secure and that there is no risk of hazardous substances escaping into the environment or contaminating the surrounding area. This requirement is part of the broader safety protocols designed to protect workers, the public, and the environment from the dangers posed by hazardous materials.

While visually inspecting, labeling, and maintaining logs are all important practices, none of them directly address the immediate hazard created by potential leaks in the same way that leak testing does. Testing verifies the integrity of the closures, which is a critical part of handling hazardous materials safely.