What types of containers are approved for handling flammable and combustible liquids?

Approved containers for handling flammable and combustible liquids must meet specific safety standards to minimize the risks associated with these hazardous materials. The correct answer highlights that only approved containers and portable tanks are suitable for this purpose. These approved containers are designed and tested to withstand the properties of the materials they hold, including resistance to corrosion, pressure, and temperature extremes.

Containers must also feature appropriate labeling and safety mechanisms, such as tight-sealing caps and flame arrestors, to prevent accidental release of the contents and to reduce the risk of ignition. Using containers that do not meet these safety standards significantly increases the risk of spills, leaks, and fires.

The other options suggest a variety of container types that do not meet OSHA regulations. For example, plastic containers are not universally accepted since not all plastics can safely contain flammable liquids. Metal containers can be safer, but they must still be specially designed and approved for this use. Containers without caps provide no protection against spills or vapors, presenting a high risk when dealing with flammable substances. Thus, the importance of using only approved containers and portable tanks cannot be overstated when handling flammable and combustible liquids.