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A TIH material is a liquid or a gas known to be so hazardous to humans that it poses a hazard to health during transportation or, in the absence of adequate data on human toxicity, is presumed to be toxic to humans based on tests conducted using laboratory animals. A TIH has an LC50 value of not more than 5,000 ppm, indicating the lethal concentration to 50% of the laboratory animals tested. Hazard zones have been assigned to TIH materials in an attempt to classify the severity of the inhalation hazard in terms of LC50. For example, a Hazard Zone A material would be more toxic than a Hazard Zone D material.
Many isolation and downwind distances were revised, both upward and downward, between the 1993, 1996 and 2000 editions of the ERG, and there have been additional adjustments in the 2004 edition. Fluctuations occur because of improvements in computer modeling, which is used to determine such distances.
A graphic showing set-up of initial isolation and protective action guide distances is on pages 300 and 301. When a material in the yellow or blue section is highlighted, responders should go directly to the green section to obtain isolation and evacuation distances.
Distances in the green section are divided into small spills and large spills. A small spill consists of a single individual package or container, usually 55 gallons or less in capacity. Large spills involve a large package or container, or multiple small packages or containers. Spills are further divided into day and night events. Day spills are considered any time between sunrise and sunset, and night spills anytime between sunset and sunrise. Isolation distances and downwind protection distances are identified for both day and night spills. This is done because the air is more stable at night and vapor clouds will travel farther than during the day.
Dangerous water-reactive materials are also listed at the end of the green section. These listings should be used only when materials are spilled in water or when firefighting will cause a water reaction. Types of toxic vapors released in a water reaction with listed water-reactive materials are identified in this section. The potential TIH gases released when water reactive materials are in contact with water also are shown.
Several new contact numbers have been added in the 2004 ERG. If the material spilled is a marine pollutant or if oil products are spilled on the water, the National Response Center (NRC) should be notified. If “RQ” is listed on the shipping papers, the material is a reportable quantity of the hazardous material and, if spilled, the NRC must be contacted. The NRC is the notification, communications, technical assistance, and coordination center for the National Response Team (NRT). It can provide information on chemicals through its OM-TADS database. The NRC can also provide facilities for conducting conference calls with over 20 different parties on the incident scene. NRC should also be contacted to report chemical or biological terrorist attacks.
Pages 11 and 372 of the ERG provide information about emergencies involving military shipments. Two contact numbers are provided: for explosives or ammunition incidents call 703-697-0218 (collect calls are accepted); and all other dangerous goods incidents should be referred to 800-851-8061. These numbers are for emergencies only. A glossary of terms is provided on pages 358 to 365.
Free copies of the ERG are provided by the DOT to all police, fire, EMS and other emergency response organizations through a selected agency in each state. Your state agency can be determined by contacting the DOT Office of Hazardous Materials Transportation Research and Special Programs (RSPA) at 202-366-0656. State contacts for the ERG are also listed on the DOT website at http://hazmat.dot.gov/gydebook.htm.
The author has developed a training course for the ERG available in a PowerPoint CD-ROM version. In addition, each CD contains an electronic version of the ERG, a DOT Chart 12, an instructor guide, a student manual, lists of state ERG contacts and private-sector sources, a certificate template and a final exam. Information may be obtained at email@example.com, by fax at 410-760-2549 or at www.hazardousmaterialspage.com.