What hazard do OSSF installers face that is less common among other construction workers?

The correct choice is related to the unique environmental conditions that OSSF (On-Site Sewage Facility) installers often encounter. Unlike those in general construction, OSSF installers frequently work with systems that involve handling, installing, or maintaining sewage and wastewater treatment equipment. This exposure places them at a greater risk of encountering infectious waterborne diseases, which can be transmitted through contact with contaminated water or soil.

Working with sewage systems means that installers might be exposed to pathogens that thrive in unsanitary conditions. These can include bacteria, viruses, and parasites that can lead to various illnesses. This specific risk is less common in many other construction settings, where the hazards are more associated with physical injuries from machinery, falls, or electrical work.

The other hazards mentioned, while still possible in any construction environment, do not uniquely apply to OSSF installations in the same context as the risk from infectious diseases. Thus, the focus on waterborne diseases highlights the unique health risks related specifically to the nature of OSSF work.