Hazardous Materials Incidents - Definition and Hazard Description

With the exception of severe storms and flooding, hazardous materials incidents are perhaps the most likely to affect you as a citizen.  Every county has at least one facility that produces, stores or uses some form of hazardous material.  Every water treatment plant, for example, has chlorine on-site to rid the water of bacterial contaminants.  Additionally, hazardous materials are transported down many roads every day.  People living in rural areas typically don't think about the propane trucks driving up and down their residential streets as carrying a hazardous material, but it is one of the most commonly found materials in your community.  Even the natural gas we use on our homes must be treated as a dangerous substance when a leak occurs.

HazMat incidents typically take two forms, fixed facility incidents and transportation incidents.  The major difference between the two is that it is reasonably possible to identify and prepare for a fixed site incident, because laws require those facilities to notify state and local authorities about what is being used or produced there.  Transportation incidents are substantially harder to prepare for, however, because you never know what material(s) could be involved until the accident actually happens. 

Hazardous Materials Transportation Incident

This is any occurrence resulting in uncontrolled release of materials, during transport, that are capable of posing risk to health, safety, and property as defined by Department of Transportation Materials Transport regulations. Each year, about 250,000 shipments of hazardous materials crisscross the state of Tennessee. Incidents such as the propane explosion in Waverly in 1978 and the bromine spill in Rockwood occur several times a year throughout the state. Additionally, thousands of shipments of radiological materials, mostly medical materials and low-level radioactive waste, take place across the state. Many incidents occur in sparsely populated areas and affect very few people. There are occasions, however, where materials are involved in accidents in areas with much higher population densities such as the propane tanker explosion in Memphis on December 23, 1989, that killed eight people. Fortunately, such events are rare. Hazardous materials transportation incidents can occur at any place within the state, although the vast majority occur on the interstate highways or major federal or state highways, or on the major rail lines. These events can affect anywhere up to several thousand people, and significant events occur slightly less than 50 times per year.

Fixed Facility Hazardous Materials Incident

This is any occurrence of uncontrolled release of materials, from a fixed site, capable of posing a risk to health, safety, and property as determined in the EPA's Resource Conservation and Recovery Act. These materials are classed identically to those specified in the section on transportation accidents. Hazardous materials incidents of this type occur several times a month in many of the counties in Tennessee. Major events (i.e., those requiring significant evacuations) occur approximately six times per year across the state.

Interstate Pipeline Hazardous Materials Incident

There are a significant number of interstate natural gas, heating oil, and petroleum pipelines running through Tennesse.  These are used not only to provide natural gas to the utilities in Tennessee, but transport these materials to the northeastern portions of the country from production areas along the Gulf Coast.  Significant releases from these facilities occur, on average, twice a year, affecting anywhere from a handful to several dozen people at a time. 

Identifying the Hazards In Your Community

There are several ways to determine what the risk from hazardous materials are in your community.  There are maps available that show where the major transportation routes and pipelines are across the state, and the U. S. Environmental Protection Agency now has a mapping web site that allows you to look up all of the EPA-regulated facilities within your community.

Additionally, both the State Emergency Response Commission and your Local Emergency Planning Committee have records that show what fixed facilities are present in your community and exactly what they have on-site that could pose a hazard to you and your family.

· State Hazard Maps

§ Major Natural Gas Pipelines in Tennessee

§ Major Petroleum Pipelines in Tennessee

§ Major Railways in Tennessee (under development)

§ Major Highways in Tennessee

· Use EPA's EnviroMapper Program.