A way that personnel and equipment become contaminated is by:

• A. Parking apparatus upwind
• B. Working in the cold zone
• C. Secondary contamination
• D. Working upwind and uphill from the hot zone

Answer: (D)

Contamination risk comes from exposure to the hazardous material and from transferring that material onto personnel or equipment as you move through the incident scene. The contaminant plume tends to travel with the air and, on sloped terrain, can move downhill as well. Therefore, being upwind and uphill from the hot zone puts you on the side where the plume is moving away from you and on higher ground where contaminants are less likely to accumulate. This positioning directly reduces the chance that you or your gear will become contaminated, making it the best protective choice.

Other options don’t offer the same protection. Parking equipment upwind isn’t by itself a contamination route; it may reduce exposure but doesn’t describe how contamination would occur. Working in the cold zone is safer, but contamination can still spread into or from that area if decontamination isn’t performed properly. Secondary contamination is a real hazard when contaminated material or gear is carried into clean areas, but the emphasis here is on preventing exposure by proper positioning relative to the plume.