Catastrophic event preparedness. Catastrophic ammonia emergencies occur for two main reasons: Responders are not prepared to act swiftly to mitigate the problem safely when it is small or there is an unanticipated explosion, flash fire, or valve failure that immediately releases a large aerosol stream. The overall game plan for addressing an ammonia emergency depends on the response team’s understanding of and preparation for the hazards, risks, and threats. The One Plan provides a Hazard Analysis Quick Guide (Figure 1) to judge the possibility of a catastrophic event. The 30-Minute Plan Emergency Control Guide provides checklist readiness reminders to ensure that the proper actions are taken to prevent, mitigate, and respond to the threats to avert a catastrophic event.
Figure 1. Hazard Analysis Quick Guide
Hazards are the chemical/physical characteristics of the products stored in the hazard area. Risks are the probability or likelihood of life safety, environmental damage, and property loss concerns within the Initial Isolation and Protective Action distances. Threats include potential fire/explosion, release, or overpressure circumstances.
Emergency responders should train routinely and develop muscle memory for ammonia’s hazards, risks, and threats. The Hazard Analysis Quick Guide offers reminders for dealing with the emergency challenges during the Discovery and Initial Response phases (life safety, rescue, and emergency shutdown). One Plan provides a more detailed hazard analysis to support the hazmat technicians’ safety before they enter the hot zone to contain, control, and mitigate the emergency event.
The decisions that a first-in officer makes for an ammonia emergency closely parallel the logic used for managing a structure fire. The response plan starts with assessing life safety and the need for rescue.
ASTI created the Hazard Analysis Quick Guide to give the first-in officer information to determine the risk-vs.-gain of a rapid-entry rescue involving ammonia. The Level of Concern (LOC) associated will indicate the status of the release.
The guide first provides data concerning ammonia’s flammability, high pressure, and the National Fire Protection Association 704, Standard System for the Identification of the Hazards of Materials for Emergency Response, reminders.
The IC determines the size of the Initial Isolation Zone, based on the U.S. Department of Transportation Emergency Response Guidebook Table 1 distances. This will be the area of highest life threat for the first 30 minutes.
The LOC will give the IC a method of gauging the progress of the incident. If the LOC is low (Level 1 or 2), the incident is less likely to grow quickly than if the LOC is 3 (uncontained and uncontrolled). The decision to enter for a rescue is safer when emergency shutdown has occurred and conditions are improving.
The officer in charge must decide whether the victim is viable. The National Advisory Committee for the Development of Acute Exposure Guideline Levels (AEGL) developed them to help national/local authorities and private companies deal with emergencies involving spills or other catastrophic exposures. The Environmental Protection Agency (EPA) recommends that emergency responders use the AEGL to describe the risk to humans resulting from once-in-a-lifetime (rare) exposure to airborne chemicals. The listings for the AEGL indicate the beginning level of exposure for each of the three levels:
- AEGL 1: Not disabling and transient and reversible upon cessation of exposure.
- AEGL 2: Could experience irreversible or other serious, long-lasting adverse health effects or an impaired ability to escape.
- AEGL 3: Above which it is predicted that the general population, including susceptible individuals, could experience life-threatening health effects or death.
The likeliness of surviving levels above 5,000 ppm for more than a few minutes is very low.
For more details about the use of AEGL guidelines, go to http://www.epa.gov/oppt/aegl/pubs/define.htm.
Rescue risk vs. gain. The first responder should consider AEGL 3 when deciding the viability of a rescue for a victim who is in an ammonia vapor cloud above 2,700 ppm for more than 10 minutes. ASTI recommends that rescue is appropriate if the levels are between 2,700 and 5,000 ppm. The decision to make a rescue also includes consideration of the growth of the release during the five to 10 minutes it takes to make the rescue. The plant operator’s completion of emergency shutdown and ventilation will reduce the risk and threat of the release, making rapid-entry rescue decisions more viable. ASTI does not recommend entry into a cloud of ammonia anywhere close to an aerosol stream of ammonia; poor visibility and cold temperatures are serious threats to the responder, and the victim will not likely survive more than a few minutes in that level of exposure.
Validation of response recommendations. ASTI does live-ammonia training with industrial and public safety responders. Rapid-entry rescue while wearing turnouts or overalls (with full-length pants inside) within an environment of 5,000 ppm of ammonia VAPOR (without the presence of a dense gas cloud or an aerosol stream) has been acceptable.
The IC must make critical life safety decisions starting with the escape route or shelter-in-place plan-it is often more logical to move people to a safe refuge inside the building. The AEGL levels help the IC to determine the risk associated with vapor exposure to those moving to the rally point vs. those sheltered inside. The eye-level wind movement is also critical when defining the Exclusion Zone (Hot Zone) and movement of personnel. The wind sock on the roof will show the downwind threat while the eye-level wind is bouncing off the building walls going in the opposite direction within the Isolation Zone.
The ammonia One Plan stresses the value of the emergency shutdown procedures for reducing the risk and threat of an emergency. A playbook of actions needed to control sources of ignition, isolate the flow to the release point, manage pressure, and ventilate dangerous vapor can be accomplished by trained plant responders while working outside of the IDLH atmosphere (300 ppm). It is very important that the public safety responders recognize that the plant responders have been trained to engage this plan before an emergency occurs. The fire department officer-in-charge is more likely to support emergency shutdown knowing that a trained and properly equipped plant responder is doing it.
The threats associated with an aerosol stream can be significantly reduced by engaging the “tarp-and-cover” tactic. ASTI has more than 25 years of experience working with tarp-and-cover aerosol containment. The contained aerosol release recondenses into a liquid and settles into a puddle of liquid that is much less dangerous. A properly equipped hazardous materials technician-trained team must perform the tarp-and-cover action when working within a dense gas cloud or near an aerosol stream. The aerosol will easily reach –60°F to –80°F. ASTI works with responders to work outside the dense gas aerosol to place the tarp.
When hazmat technician-level responders arrive, the highest immediate life safety and emergency shutdown challenges should already be managed. The One Plan offers the command team packets that include the following:
- Playbook details (pictures, diagrams, and checklist reminders).
- Incident Command System (ICS) 201 Initial Incident Action Plan.
- ICS 208 Site Safety and Control Plan.
- A Detailed Hazard Analysis.
Deciding whether to enter the Hot Zone is tied directly to the level of personal protective equipment (PPE) training and the ability to monitor the ammonia vapor. The protections PPE affords are summarized at the bottom of the Hazard Analysis Quick Guide.
It is very important to train on the One Plan readiness, especially emphasizing the integration of public safety and plant emergency responder activities. The details of how to accomplish the life safety and emergency shutdown procedures should be on top of the list on the responder teaming agreement. The technical information and review of playbook details relating to an IAP that requires entry into a Hot Zone are essential parts of the annual walk-through training session. ASTI has sample versions of the Teaming Agreement and a lesson plan for performing a joint training session between industry and public safety while using the One Plan.
All-hazards. The One Plan system is designed to provide an all-hazards approach to managing emergencies. The operational tools (playbooks, checklists, and guidance summaries) can all be easily adapted to fire, other chemicals, disaster circumstances, and so forth. The command team and method of integrating response between industry and public safety used for ammonia response can be used by responders dealing with an industrial accident, a medical emergency, a bomb threat, or other type of event. The checklist and other guidance details would change for the specific circumstance.
Industry and fire service leaders agree that the Integrated Contingency Plan (One Plan) provides the most effective emergency planning guidance for the discovery, initial response, sustained response, and termination phases of an emergency. ASTI has created the One Plan checklists, playbooks, and quick guides mentioned above for an anhydrous ammonia response to help emergency responders “operationally” engage the plan in a timely, safe, and effective way.
The four most pressing concerns about ammonia expressed by firefighters trained by ASTI over the past four years (listed at the beginning of this article) have provided a great framework on which to focus the operational guides and the training plan. The issues associated with ammonia risk and threat can be minimized when the emergency responders understand the hazards, risks, and threats of an emergency. The team connection among plant responders, first-in public safety response, and the hazmat team relates directly to the checklist recommendations of the One Plan.
Note: The Ammonia Safety and Training Institute Web site www.ammonia-safety.com offers podcast training and other information on how to implement the One Plan in your community. ASTI will work with departments to sponsor local area classes. We also present free Safety Day training sessions across the country.
GARY W. SMITH is the president of the Ammonia Safety and Training Institute, founded in 1992. He retired in 2003 as chief of the Watsonville (CA) Fire Department.
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