TRAFFIC INCIDENT MANAGEMENT IN HAZARDOUS MATERIALS SPILLS IN INCIDENT CLEARANCE
2.0 TYPES OF HAZARDOUS MATERIALS AND HAZARDOUS MATERIAL SPILLS
Since they are such an integral part of our lives, hazardous materials are essential to the United States (U.S.) economy and its citizens. Large sectors of the U.S. economy, including agriculture, manufacturing, construction, mining, and medical and sanitary services, utilize hazardous materials. Hazardous materials fuel our vehicles, fight viruses and bacteria, as well as heat and cool homes. Yet, because of their physical, chemical, or nuclear properties, hazardous materials may pose a threat to public safety or the environment during transportation.
Millions of tons of flammable, corrosive, poisonous, and radioactive materials are transported daily in the U.S. The majority of hazardous materials cargoes make it to their destinations safely; yet some incidents do occur. Most of these incidents involve incidental releases, but occasionally there are more serious threats to life or property. This section discusses the basics of these incidents (basic vehicle fluid spills versus cargo spills), and department of transportation (DOT) hazard classes, grouping system based on the physical and chemical properties.
Understanding Hazardous Material Spills
Hazardous material spills that result from a traffic accident are either spills of vehicular fluids, hazardous material cargoes, or a combination of both.
Vehicular fluid spills are releases of materials that are used in a vehicle’s operation. The size of the release is usually small and limited to the amount used in vehicle operations. The most common hazardous materials used in vehicles include fuel (diesel or gasoline), radiator coolant (ethylene glycol), transmission fluid, hydraulic fluid, brake fluid, windshield washer fluid, and battery acid. Other less common materials that are used in vehicles include ethanol, propane, and compressed natural gas (CNG), though propane and CNG quickly transform to their gaseous state when released.
A hazardous materials cargo spill is a release of a substance or material capable of posing an unreasonable risk to health, safety, or property when transported for commercial purposes. Unlike a vehicular fluid spill, a multitude of factors dictate the size and nature of the spill, including the type of material being transported, the original load size, the physical properties of the material, and the amount of damage to the transporting vessel.
According to the U.S. DOT Pipeline and Hazardous Materials Safety Administration (PHMSA), Office of Hazardous Materials Safety (OHMS), current research indicates that hazardous materials traffic in the U.S. now exceeds 800,000 shipments per day and results in more than 3.1 billion tons of hazardous materials annually.1 The “Hazardous Materials Incident Summary Data” 2 provided by the PHMSA OHMS, indicates that flammable-combustible liquids have consistently been involved in most incidents over the last five years. In addition, corrosive materials have steadily been involved as the second highest amounts in incidents over the last five years. Table 1 illustrates the amount of incidents by DOT hazard classifications over the last five years.
Table 1. Incidents by DOT Hazard Classification Over the Last Five Years 2
| Rank |
2002 |
2003 |
2004 |
2005 |
2006 |
2007 |
|---|---|---|---|---|---|---|
1 |
Flammable - Combustible Liquid (6,172) |
Flammable - Combustible Liquid (6,419) |
Flammable - Combustible Liquid (6,181) |
Flammable - Combustible Liquid (8,729) |
Flammable - Combustible Liquid (10,288) |
Flammable - Combustible Liquid (6,315) |
2 |
Corrosive Material (6,055) |
Corrosive Material (5,691) |
Corrosive Material (5,321) |
Corrosive Material (4,046) |
Corrosive Material (5,058) |
Corrosive Material (3,604) |
3 |
Poisonous Material (868) |
Poisonous Material (787) |
Poisonous Material (865) |
Nonflammable Compressed Gas (574) |
Infectious Substance (Etiologic) (1,067) |
Combustible Liquid (980) |
4 |
Miscellaneous Hazardous Material (493) |
Miscellaneous Hazardous Material (578) |
Miscellaneous Hazardous Material (544) |
Miscellaneous Hazardous Material (516) |
Combustible Liquid (1,042) |
Nonflammable Compressed Gas (865) |
5 |
Oxidizer (430) |
Oxidizer (454) |
Oxidizer (464) |
Poisonous Materials (379) |
Nonflammable Compressed Gas (598) |
Oxidizer (387) |
A 2004 publication by the Federal Motor Carrier Safety Administration (FMCSA)1 indicates that hazardous material crashes, fatalities, and injuries are low relative to the amount of hazardous materials moved on U.S. highways. However, hazardous material incidents have significant cost impacts on property and the economy.
The U.S. Census Bureau estimates that 11 percent of all freight transported by trucks is hazardous material and 7 percent of all truck ton-miles of freight are hazardous material; and the U.S. DOT estimates that 7 percent of all trucks are carrying hazardous material. Motor carriers that transport hazardous materials, their drivers, and the federal, state, and local government agencies that regulate the transportation of hazardous material can take satisfaction in the fact that hazardous material crashes are under-represented in the overall crash picture.
Despite these data, the transportation of hazardous material by trucks imposes significant costs on the transportation system. According to a 2001 Battelle report to FMCSA as referenced in the 2004 FMCSA publication,1 highway crashes involving hazardous material shipments have a societal cost impact of slightly more than $1 billion a year. Furthermore, a single crash of a truck transporting hazardous material in a crowded area has the potential for deaths and injuries far beyond that of a truck carrying non-hazardous material cargo. Extensive property damage and economic and personal disruption from immobilizing traffic and/or evacuation of homes and businesses is not uncommon in hazardous material crashes. In this light, the finding that liquid hazardous materials are more likely than liquid non-hazardous cargo to be spilled or released as the result of a highway crash is of great concern. FMCSA recognizes the potential for severe hazardous material highway crashes and has increased its emphasis on safety programs in this area over the past 3 years.1
DOT Hazard Classes (Categories Based On Physical and Chemical Properties)
The U.S. hazardous material regulatory system is a risk-based system that focuses on identifying the hazard and reducing the likelihood of a hazardous material release. Under the DOT’s Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180)3 hazardous materials are categorized by analysis and experience into hazard classes and packing groups. Each shipper is required to classify a material according to these hazard classes and packing groups and communicate the material’s hazards. The shipper repetitively communicates the hazard through the use of package labels, shipping papers, and placards on transport vehicles.
The DOT has broad jurisdiction to regulate hazardous materials that are in transport, including the discretion to decide which materials shall be classified as “hazardous.” These materials are placed in one of nine hazard classes based on their chemical and physical properties. The hazard classes may be further subdivided into divisions based on their characteristics. Additionally, some materials may be reclassified as combustible materials or "other regulated materials" (ORM-D) because of limited hazard during transport. These properties and characteristics are crucial in understanding the dynamics of a spill during a traffic incident. Therefore, it’s important for response personnel to understand the hazard classes, their divisions, and reclassified materials:
- Class 1: Explosives
- Division 1.1 Explosives with a mass explosion hazard
- Division 1.2 Explosives with a projection hazard
- Division 1.3 Explosives with predominantly a fire hazard
- Division 1.4 Explosives with no significant blast hazard
- Division 1.5 Very insensitive explosives
- Division 1.6 Extremely insensitive explosive articles
- Class 2: Gases
- Division 2.1 Flammable gases
- Division 2.2 Nonflammable gases
- Division 2.3 Poison gases
- Class 3: Flammable liquids.
- Liquid material with a flash point of not more than 60° C (140° F), or any material in a liquid phase with a flash point at or above 37.8° C (100° F) that is intentionally heated and offered for transportation or transported at or above its flash point in a bulk packaging.
- Combustible liquid
- Any liquid that does not meet the definition of any other hazard class specified in the HMR and has a flash point above 60 °C (140 °F) and below 93 °C (200 °F);
- A flammable liquid with a flash point at or above 38 °C (100 °F) that does not meet the definition of any other hazard class may be reclassified as a combustible liquid.
- Class 4: Flammable solids; spontaneously combustible materials; and materials that are dangerous when wet
- Division 4.1 Flammable solids
- Division 4.2 Spontaneously combustible materials
- Division 4.3 Materials that are dangerous when wet
- Class 5: Oxidizers and organic peroxides
- Division 5.1 Oxidizers
- Division 5.2 Organic peroxides
- Class 6: Poisons and etiologic materials
- Division 6.1 Poisonous materials
- Division 6.2 Etiologic (infectious) materials
- Class 7: Radioactive materials
- A material that spontaneously gives off ionizing radiation where the activity concentration or total activity exceeds the values specified for certain radionuclides in the HMR.
- Class 8: Corrosives
- A material, liquid, or solid that causes visible destruction or irreversible alteration to human skin; or a liquid that has a severe corrosion rate on steel or aluminum.
- Class 9: Miscellaneous
- A material which presents a hazard during transport, but which is not included in any other hazard class (e.g., a hazardous substance or a hazardous waste).
- ORM-D: Other regulated material
- A material which, although otherwise subjected to regulations, presents a limited hazard during transportation due to its form, quantity, and packaging.
