Friday, October 18, 2013

Ammonium Nitrate (AN): Safe Storage, Handling, & Management Part 4

Emergency Response

Owner/operators of storage facilities should develop a site emergency response plan which includes:

• Coordination with local first responders
• Joint training with first responders if possible
• Employee training
• Community outreach
• Analysis of what may be at risk in a serious accident and appropriate planning
• Signs that clearly mark high hazard areas, safe areas, emergency contact numbers, firefighting equipment, and other essential area during an emergency response
• A site and area evacuation plan

Owners and operators of facilities holding AN have an obligation to ensure their community’s first responders are aware of the hazards associated with the AN. Reliance on a report may not always be sufficient. Owners and operators should take a pro-active approach to reaching out to the emergency response officials in their location and ensuring that the hazards of AN are understood by the responders.

What do firefighters need to know when responding to an accident or fire involving AN?

Before responding to a fire involving AN, firefighters should ensure the community emergency response plan includes:

• AN hazard information and emergency response guidelines
• Quantity, storage types, and locations of AN at facilities in their community
• Specific response procedures; including a decision process to determine under which conditions a fire should be fought or whether the fire should be allowed to burn
• Evacuation procedures for the community
• Training requirements for all response personnel
• A schedule for exercising the response plan related to AN accidents

When responding to a fire where AN is stored; firefighters should:

• First consider if they can safely fight the fire or whether they should just let it burn, move to a safe location, and focus on evacuating nearby residents and preventing further safety issues for the surrounding community.

To determine whether or not it makes sense to fight the fire or to let it burn, firefighters and emergency responders should consider the following information:

• Firefighters should not fight an AN fire and everyone, including fire fighters, should be evacuated to a safe distance if they observe any of the following:
o A fire involving AN is judged to be out of control;
o The fire is engulfing the AN; or
o Brown/orange smoke is detected, indicating the presence of nitrogen dioxide (which is toxic); or
o A rapid increase in the amount/intensity of smoke or fire in the area of AN storage.

• If firefighters consider it safe and appropriate to respond to a fire involving AN, then the following information should be considered:
o AN fires should be fought from protected locations or maximum possible distance. Approach a fire involving or close to AN from upwind to avoid hazardous vapors and toxic decomposition products. Self-contained breathing apparatus (SCBA) of types approved by the National Institute for Occupational Safety and Health (NIOSH) should be used to protect personnel against gases.
o Use flooding quantities of water from a distance as promptly as possible. It is important that the mass of AN be kept cool and the burning be quickly extinguished. Keep adjacent fertilizers cool by spraying with large amounts of water. When possible and appropriate, only use unmanned hose holders or monitor nozzles.
o Do NOT use steam, CO2, dry powder or foam extinguishers, sand or other smothering agents.
o Ensure maximum ventilation of the AN storage container as quickly as practical to prevent heat and pressure buildup. This is different than ensuring maximum ventilation of the entire building or structure where the AN is stored. Ventilation of the structure should be conducted only in a manner to limit fire spread and growth and should be minimized until a suppression water supply is established.
o If practicable and safe to do so, attempt to prevent AN from entering the drains where explosive confinement could occur. Remember AN may be washed into drains by fire water, but it can also melt and flow without impetus from water.
o Prevent or minimize contamination of water bodies or streams to reduce the potential for environmental effects.

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