Closed-head drums have a permanently attached lid with one or more small openings. What are these small openings called?

The small openings in closed-head drums are referred to as bungs. These are specifically designed to allow for the safe filling and emptying of the drum's contents while maintaining the integrity of the closed head design. Bungs provide a means to access the material within the drum, typically using appropriate tools that fit the threading of the bung, ensuring that the drum remains sealed during transport and storage while also facilitating easy handling during usage.

Bungs are an essential component of closed-head drums because they help to prevent leaks and spills, which is critical in the context of hazardous materials to ensure safety and compliance with regulations. Their design allows for pressure relief and minimizes the risk of vapor escape, making them suitable for applications involving chemicals and other hazardous substances. This distinction underscores their importance in handling materials responsibly and in accordance with safety standards.