Contaminated Runoff

What Is Contaminated Runoff?

Contaminated runoff is water, often the department's own fire attack or decon water, that has picked up hazardous product and is now carrying it toward a storm drain, creek, or waterway. This isn't limited to spill incidents; it's a routine concern on structure fires and vehicle fires too, since firefighting foam runoff (especially older AFFF containing PFAS) and fuel-contaminated fire attack water can themselves become the contamination problem even when the original incident wasn't a hazmat call. Standard mitigation is plugging or covering nearby storm drains before knockdown begins, diking runoff into a containment area rather than letting it flow freely, and, where required by local environmental regulation, notifying the water authority or environmental agency of a suspected release into a storm or sanitary system.

Why Contaminated Runoff Matters on the Fireground

It's easy to focus entirely on extinguishing the fire or stopping the leak and forget that the water used to do it is now a hazmat problem of its own, one that can end with fuel or foam concentrate in a creek miles from the original scene. Plugging storm drains before attack begins, not after runoff is already flowing, is the difference between a contained incident and a secondary environmental release that draws regulatory attention after the fact.

Relevant NFPA Standards

• NFPA 470: Hazardous Materials/Weapons of Mass Destruction (WMD) Standard for Responders
• OSHA 29 CFR 1910.120: Hazardous Waste Operations and Emergency Response (HAZWOPER)

Field Procedures & Tactical Steps

1. Identify nearby storm drains, ditches, or waterways before beginning fire attack, foam application, or decon on any incident with a fuel or chemical component.
2. Plug or cover accessible storm drains proactively, before runoff begins, rather than reacting once contaminated water is already flowing.
3. Dike or divert runoff into a containment area using available berm material, absorbent boom, or existing low points on the site.
4. Notify the appropriate environmental or water authority if runoff has reached or is likely to reach a storm drain, creek, or sanitary sewer system, per local reporting requirements.

Common Context & Application

Comes up on any fire or spill near a storm drain, waterway, or sanitary sewer, when the officer has to decide whether to plug drains and dike runoff before or during suppression, not after the fact.

Frequently Asked Questions about Contaminated Runoff