Why are gasoline and volatile solvents objectionable when present in a sewer?

• A. They tend to cause the solids to vaporize
• B. They produce an explosion hazard
• C. They will coagulate floatables and cause stoppages
• D. They represent wasted resources

Answer: (B)

Gasoline and volatile solvents are objectionable in a sewer because they can create an explosion hazard. These liquids release vapors that mix with air to form potentially explosive mixtures. In sewer systems, spaces are often confined and poorly ventilated, so vapors can accumulate in manholes, pipes, and at treatment facilities. If an ignition source—such as electrical equipment, motors, or static discharge—reaches these vapors, a detonation or fire can occur, posing serious danger to workers and infrastructure.

The other ideas don’t fit as well. Gasoline and solvents are liquids that vaporize to form flammable vapors, not solids that would vaporize; they don’t coagulate floatables or cause stoppages in a way that would be the primary hazard. And while improper disposal is wasteful, the immediate safety concern in sewers is the risk of ignition from flammable vapors.