Highway Hazardous Materials Accident Extrication Issues

By Stephen L. Hermann

From the 2009 vehicle extrication e-Newsletter, sponsored by

One of the most challenging scenarios for first responders is one in which a person is trapped in a vehicle accident and requires extrication and there is a spill of hazardous materials involved. This article addresses three general issues involving the use of the most common resource of hazardous materials advice, the U.S. Department of Transportation (DOT) 2008 Emergency Response Guidebook (ERG2008):

1. Spills involving gasoline, diesel fuel, propane, and sulfuric acid are some of the most common scenarios you might encounter. How does the ERG2008 address them?

2.  How is the ERG2008 used to make determinations regarding isolation, evacuation, or “sheltering in place” to handle people in the vicinity who might be exposed?

3.   Situations involving radioactive materials are especially problematic, given their uncommon occurrence and most first responders’ lack of familiarity with them. How does the ERG2008 address such difficult scenarios?


SPILLS INVOLVING GASOLINE, DIESEL FUEL, PROPANE AND SULFURIC ACID

Gasoline is not only the most commonly transported hazardous material, but it is also responsible for more fatalities caused by the release of a chemical in transportation than all other hazardous materials combined. Therefore, understanding the recommended procedures when gasoline is involved is probably the most critical hazardous materials issue facing first responders at a potential extrication scene.

The 2008 Emergency Response Guidebook was developed jointly by Transport Canada, the U.S. Department of Transportation (DOT), and the Secretariat of Transport and Communications of Mexico. It is for the use of firefighters, police, and other emergency services personnel who may be the first to arrive at the scene of a transportation incident involving hazardous materials. It is primarily a guide to aid first responders in quickly identifying the specific or generic hazards of the material(s) involved in the incident and protecting themselves and the general public during the initial response phase of the incident.

In the United States, according to the requirements of the U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA, 29 CFR 1910.120) and regulations issued by the U.S. Environmental Protection Agency (EPA, 40 CFR Part 311), first responders must be trained regarding the use of this guidebook. U.S. DOT’s primary objective is to place one copy of the ERG2008 in each publicly owned emergency service vehicle.

Emergency service organizations that have not yet received copies of ERG2008 should contact the respective distribution center in their state or province.  In the United States, information about the distribution center for your location may be obtained from the Office of Hazardous Materials Safety Web site at http://hazmat.dot.gov, or call (202) 366-4900.

Isolation Distance Recommendations

After determining the hazardous material(s) involved in the incident, responders must determine how closely they may approach a spill. The ERG2008 defines the “Initial Isolation Distance” as: “a distance within which all persons should be considered for evacuation in all directions from the actual spill/leak source. It is a distance (radius) which defines a circle (Initial Isolation Zone) within which persons may be exposed to dangerous concentrations upwind of the source and may be exposed to life threatening concentrations downwind of the source.”

Like most materials listed in the ERG2008, the alphabetical listing for “Gasoline” in the blue-bordered index pages is not highlighted in green; therefore, you do not have to consult the green-bordered Table 1 – “Initial Isolation and Protective Action Distances.”. Orange-bordered pages Guide 128 is listed for “Gasoline.” For all except radioactive materials, the proper initial isolation distance recommendation  is shown as the second “bullet” (or item) in the “Public Safety” block on the left page. The second bullet entry states: “As an immediate precautionary measure, isolate spill or leak area for at least 50 meters (150 feet) in all directions.”  Until a combustible gas indicator can be used to take readings and adjust the recommended distance, all personnel must stay outside this isolation area.

As shown in the following table for the four materials of interest, the orange-bordered Guide for DIESEL FUEL is the same as for GASOLINE, number 128.


Protective Clothing Recommendations

Also in the “Public Safety” block on the left Guide page are recommendations for appropriate protective clothing for the material as shown below:

GASOLINE, DIESEL FUEL, and PROPANE:
! Wear positive-pressure self-contained breathing apparatus (SCBA).
! Structural firefighters’ protective clothing will provide only limited protection.

SULFURIC ACID:
! Wear positive-pressure self-contained breathing apparatus (SCBA).
! Wear chemical protective clothing that is specifically recommended by the manufacturer. It may provide little or no thermal protection.
! Structural firefighters’ protective clothing provides limited protection in fire situations ONLY; it is not effective in spill situations where direct contact with the substance is possible.

U.S. Occupational Safety and Health Administration (OSHA) prescribed Permissible Exposure Limits (PEL) are listed below for the four chemicals, showing that although there is no prescribed PEL for gasoline or diesel fuel, respiratory protection is mandatory if levels exceed those shown for propane and sulfuric acid. Many responders are not aware of a further requirement stated in OSHA 1910.120, subparagraph q:

“(q)(3)(iv) Employees engaged in emergency response and exposed to hazardous substances presenting an inhalation hazard or potential inhalation hazard shall wear positive pressure self-contained breathing apparatus while engaged in emergency response, until such time that the individual in charge of the ICS determines through the use of air monitoring that a decreased level of respiratory protection will not result in hazardous exposures to employees.”

Therefore, until the appropriate detection instrument(s) can establish that levels of propane or sulfuric acid are not above those stipulated by OSHA, positive-pressure SCBA remains mandatory.  


DETERMINATIONS OF “ISOLATION,” “EVACUATION,” OR “SHELTERING IN PLACE” TO HANDLE PEOPLE IN THE VICINITY WHO MIGHT BE EXPOSED

Invariably at any transportation extrication scene, there will not only be decisions involving the proper initial isolation distances to protect responders, but also how to handle either evacuation or “sheltering in place” for people downwind from the spill or leak.

Initial isolation distances were previously addressed. Look up the chemical in the blue-bordered ERG2008 alphabetical index pages. If it is highlighted in green, then you must consult the green-bordered Table 1 – “Initial Isolation and Protective Action Distances”, as will be described shortly. If the material’s name is not highlighted in green, then turn to the referenced orange-bordered guide pages, and look in the “Public Safety” block of data on the left-hand page, as noted above. Other than for keeping all other individuals a reasonable distance from the scene itself to give responders room to work, no further references are required for chemicals not highlighted in green.

Thus, for the four chemicals listed above, gasoline, diesel fuel, propane, and sulfuric acid, no further consideration is required for individuals downwind. However, those materials highlighted in green in the blue-bordered index pages require consulting the green-bordered Table 1 – “Initial Isolation and Protective Actions Distances.”

This additional downwind hazard area is called the Protective Action Zone and is defined as follows:
“An area DOWNWIND from the incident in which persons may become incapacitated and unable to take protective action and/or incur serious or irreversible health effects.”  Table 1 provides specific guidance for small and large spills occurring day or night. An extract from Table 1 is shown below.

Above from ERG2008

If the spill or leak is the size of a 55-gallon drum (200 liters) or less, it is a small spill. Larger amounts of material are considered a large spill. The Initial Isolation Distance will now be determined from either the “Small Spill” or “Large Spill” column, rather than from the second bullet in the “Public Safety” block on the orange-bordered Guide.

In the table “Day” is the period from sunrise to sunset, and “Night” is from sunset to sunrise. Select the proper time column, and read the Downwind Protective Action Distance from the table. A diagram can now be constructed to illustrate both the Initial Isolation Zone and the Protective Action Zone.

 

Above from ERG2008.

You must now decide whether to attempt to evacuate people in the Protective Action Zone or have them Shelter In-Place. Evacuate means to move all people from a threatened area to a safe place. To perform an evacuation, there must be enough time for people to be warned, to get ready, and to leave an area. If there is enough time, evacuation is the best protective action.

Shelter In-Place means people should seek shelter inside a building and remain inside until the danger passes. Sheltering in-place is used when evacuating the public would cause greater risk than staying where they are, or when an evacuation cannot be performed. Direct the people inside to close all doors and windows and to shut off all ventilating, heating, and cooling systems. 

SPILLS INVOLVING RADIOACTIVE MATERIALS

Hazardous materials transportation accidents involving radioactive materials are relatively uncommon, and most first responders have never had to address these potentially difficult scenarios. To quote from the introduction to an International Association of Firefighters (IAFF) training video dealing with response to radiation emergencies:

“Many emergency responders assume that any situation involving radioactive materials is extremely dangerous. This concern sometimes results in resource intensive efforts that may not be necessary.”

The 2008 Emergency Response Guidebook contains six orange-bordered Guides dealing with different types of radioactive materials that could be encountered in transportation accidents, Guides 161-166. However, there are a number of consistent items contained in all of the Guides that emphasize the fact that rescue, life-saving, and first aid are the highest priorities.

In the “Health” block of the “Potential Hazards” section on the left Guide page:
! Radiation presents minimal risk to transport workers, emergency response personnel, and the public during transportation accidents. Packaging durability increases as potential hazard of radioactive content increases.
! Undamaged packages are safe.

In the “Public Safety” section
! Priorities for rescue, life-saving, first aid, fire control, and other hazards are higher than the priority for measuring radiation levels.

In other words, do not wait for the hazardous materials team to arrive with detection instruments before initiating rescue, life-saving, first aid, or fire control measures.

(1) A cargo tank with a radioactive load. Photos by author.

In the “First Aid” block of the “Emergency Response” section on the right Guide page:
! Medical problems take priority over radiological concerns.
! Do not delay care and transport of a seriously injured person.

Again, do not wait for the hazardous materials team to arrive with detection instruments before initiating rescue, life-saving, or first aid measures.

(2) A leaking gasoline cargo tank.

(3) A leaking propane cargo tank.

Isolation Distance Recommendations

With the exception of the radioactive materials covered by Guide 166, the other five orange-bordered page Guides all state the same recommendation for the isolation distance in the fourth bullet of the “Public Safety” section:
! As an immediate precautionary measure, isolate the spill or leak area for at least 25 meters (75 feet) in all directions.

Guide 166 states the same advice, but since the blue-bordered index entries for the following items are all highlighted in green, Table 1 needs to be consulted.

 “Radioactive Material, Uranium Hexafluoride”
 “Radioactive Material, Uranium Hexafluoride, fissile”
 “Uranium hexafluoride”
 “Uranium hexafluoride, fissile containing more than 1% Uranium-235”
 “Uranium hexafluoride, non fissile or fissile-excepted”

The respective entries in Table 1 show that varying from the above distance of 25 meters (75 feet) is only required if the material is spilled in water.

(4) A sulfuric acid cargo tank.

(5) A train derailment.

Protective Clothing Recommendations

Guides 161 & 162 state
! Positive-pressure self-contained breathing apparatus (SCBA) and structural firefighters’ protective clothing will provide adequate protection.

Guides 163, 164 and 165 elaborate:
! Positive-pressure self-contained breathing apparatus (SCBA) and structural firefighters’ protective clothing will provide adequate protection against internal radiation exposure, but not external radiation exposure.

Guide 166 states for “Radioactive Materials-Corrosive (Uranium Hexafluoride/Water-Sensitive)”
! Wear positive-pressure self-contained breathing apparatus (SCBA).
! Wear chemical protective clothing that is specifically recommended by the manufacturer. It may provide little or no thermal protection.
! Structural firefighters’ protective clothing provides limited protection in fire situations only; it is not effective in spill situations where direct contact with the substance is possible.

The overall conclusion that can be drawn from studying all six of the ERG2008 Guides for radioactive materials is that, because these incidents occur relatively infrequently, many responders are not aware of the relatively limited hazard these items actually pose. A final consideration is that, according to both U.S. Department of Transportation and U.S. Department of Energy accident data, no fatality has ever resulted from the release of a radioactive material in a transportation accident. This fact, again, points to the extraordinary safety record of radioactive materials in transportation accidents.


***

Examining issues related to spills involving gasoline, diesel fuel, propane, sulfuric acid, and radioactive materials, and issues of isolation, evacuation, or sheltering in-place distances shows that the U.S. Department of Transportation 2008 Emergency Response Guidebook contains a wealth of advice and recommendations to steer first responders through the proper steps in a hazardous materials transportation incident.

STEPHEN L. HERMANN is a contract employee of the Las Vegas (NV) Metropolitan Police Department and a retired hazardous materials coordinator and specialist for the Arizona Department of Public Safety and Arizona’s senior state-on-scene coordinator for hazardous materials emergency response. He is past national chairman of COHMED, the national organization of state and local hazardous materials enforcement officers, and past chairman of the Commercial Vehicle Safety Alliance Hazardous Materials Committee. He has a bachelor of science degree in explosives technology and is a graduate of the U.S. Naval School Explosive Ordnance Disposal, United States Army Command and General Staff College, U.S. Army War College, and state Division of Emergency Services Hazardous Materials Technician course.

No posts to display