Which of the following is NOT a common class of hazardous waste?

When considering the common classes of hazardous waste, oils are typically classified as hazardous due to their potential to cause environmental harm and health risks, especially when spilled or improperly disposed of. They can contribute to pollution and pose significant risks to aquatic ecosystems and soil quality.

On the other hand, explosives, flammable liquids, and gases are explicitly classified as hazardous materials due to their inherent dangers. Explosives can detonate under certain conditions, flammable liquids can ignite and cause fires, and gases can be toxic or may create explosive mixtures in the presence of air.

Oils, while they can be hazardous, are generally not categorized with the same urgency as explosives, flammable liquids, and gases when considering immediate risk factors associated with hazardous waste classifications. The distinction rests in the regularity and conditions under which these substances pose risks, marking oils as a less immediate concern in the context of hazardous waste classification.