MPM3 (milligrams per meter) = Contact Hazard.

• A. Inhalation hazard
• B. Thermal hazard
• C. Contact Hazard
• D. Radiation hazard

Answer: (C)

The main idea is how the unit of measure relates to the route of exposure. Milligrams per meter describes how much contaminant is present along a length of surface or boundary, which is directly about what could transfer to the skin when someone touches or handles that area. That makes it a measure of potential dermal, or contact, exposure.

Inhalation hazards are about how much contaminant is present in the air, usually expressed as milligrams per cubic meter (mg/m3) to reflect concentration in a volume of air. Thermal hazards deal with heat or temperature and are described by temperature, heat flux, or similar heat-transfer metrics, not mass per length. Radiation hazards use dose units like rem or sievert to express biological effect from radiation, not surface contamination.

So the milligrams per meter unit aligns with contact hazards because it quantifies the amount of contaminant available for transfer through touch, rather than through breathing, heat transfer, or radiation exposure. For example, a contaminated surface with a certain mg/m length indicates how much material a person could transfer to their skin per meter of contact.