IDENTIFYING HAZ MATS: DOT’S HM-181

IDENTIFYING HAZ MATS: DOT’S HM-181

A haz-mat call You feel pretty comfortable about responding to one after having taken a few courses; after all, you’re better prepared than you were a few years ago when everyone was talking haz mat, but no one was familiar with the DOT Guidebook or incident command. You’ve asked the driver for his shipping papers, and now you’re looking at them. But what you’re looking at is something you don’t quite remember seeing in this form before; it’s not what you expected to see. You read it: “Corrosive liquid, flammable, n.o.s. 8 (corrosive material), UN2920, PG 1, RQ (contains…), 75,000 KG, placarded CORROSIVE.”

This information confuses you. Is the liquid corrosive or is it flammable? What does “PG” mean? Is the weight 75,000 pounds or 75,000 kilograms? The meaning doesn’t get much clearer even after you look up UN 2920, does it? The reason for the confusion is that these shipping papers were prepared under the DOT’S hazardous materials regulation, HM-181.

When the Department of Transportation was formed in 1966 by an act of Congress, it assumed many of the responsibilities previously held by the Interstate Commerce Commission. Over the past 25 years, a number of DOT regulations and acts have been introduced to protect the public from the potential hazards presented by the transporting of hazardous materials.

HM 181 HAZARDOUS MATERIALS LABELING CHART

Copyright 1991 & Published by J. J KELLER & ASSOCIATES, INC.. Neenah, Wl 54957-0368 • USA • (800) 327-6868

On December 21, 1990, the DOT issued the final rule PerformanceOriented Packaging Standards; Changes to Classification, Hazard Communication, Packaging and Handling Requirements Based on UN Standards and Agency Initiative, commonly referred to as HM-181.

Table 2

HAZARDOUS PRECEDENCE*

1. Class 7 (other than limited quantity)
2. Div. 2.3 (Poison Gas)
3. Div. 2.1 (Flammable Gas)
4. Div. 2.2 (Nonflammable Gas)
5. Div. 6.1 (Poison-Inhalation Hazard)
6. Div. 4.2 (Pyrophoric)
7. Div. 4.1 (Self-Reactive)
8. This group is based on the DOT Procedure Table based on hazard class and packing group:

Classes 3 & 6

Div. 4.1, 4.2, 4.3, 5.1, and 6.1

1. Combustible Liquid
2. Class 9 (Miscellaneous)

*Based on Hazardous Materials IHl.The Guide for Shippers, Handlers and Transporters, copyright 1991 J.J. Keller & Associates, Inc.

This rule presents a comprehensive group of changes to the DOT’S hazardous-material regulations contained in CFR 49, Parts 171 to 180. The changes are designed to shorten and simplify many of the regulations and to bring them in line with the United Nations (IJN) standards while simplifying packaging requirements. There are many provisions in this regulation, but only those dealing with hazardous-materials measurements, classifications, placards, and labeling are covered here, since they are relevant to haz-mat incident responders.

HAZARD CLASSES

Under HM-181, there are 11 hazard classes (nine numbered and two unnumbered)—classes 1 through 9, plus the classes Combustible Liquids and ORM-D. Many of these classes are subdivided into divisions, which have numeric decimal values; gases, for example, are covered under Class 2. This class is broken down into 2.1 flammable gas; 2.2 nonflammable, nontoxic gas; and 2.3 poison gas (see Table 1).

The numerical value for each primary class is shown at the bottom of labels and placards. Numerical values are used so that non-English-speaking responders worldwide can recognize the Arabic numerals and take appropriate actions.

Classes 3, 4, 5,6, 8, and 9 each have an assigned packing group (PG) that appears on the shipping papers. These groups are based on the degree of hazard presented by the materials. This designation’s appearance on the shipping papers is important to the shipper, since it affects the way the load is handled. Responders, too, should be familiar with the data given on the shipping papers because the information gives them an idea of the dangers represented by the hazardous materials involved.

The packing group classifications are

• Packing Group I = Great Danger
• Packing Group II = Medium Danger
• Packing Group III = Minor Danger

Materials in divisions 2.3 (poisonous gas) and 6.1 (poison) may be toxic by inhalation. The regulations describe criteria for this classification, which depend on the I.C₅₀ (lethal concentration that kills 50 percent of a test animal population) for the gas and LC₅₀ and volatility for a 6.1 material. The words “Inhalation Hazard” must be part of the description on the shipping papers. This is required on nonbulk packaging as well. On bulk packaging (tank truck, tank car), it must be shown on opposite sides.

The maximum temperature for a flammable rating is being raised from 100°F to 141°F, making the combustible range above 111 °F to 200°F. ‘ITiis revision makes the U.S. flammables classification the same as that of the rest of the world. It also makes the DOT definition of flammability more consistent with the Environmental Protection Agency’s hazardous waste definition of ignitability.

letters of the alphabet are used to categorize explosives for consistency in storage conditions.

MULTIPLE HAZARDS

The HM-181 regulations, which consider hazardous materials with multiple hazards, contain a hazardranking tabic that defines primary and secondary hazards in order of precedence (see Table 2). Chemicals that meet multiple definitions of hazards can be assigned only to one class or division. T he assigned hazard is called the primary hazard.

Hazardous materials assigned multiple hazards must have individual labels for each hazard. The hazard name must be spelled out on the primary hazard label but not on the labels for secondary classes. This procedure allows the responder to identify immediately the primary hazard from the labels on the container of a material with primary and secondary hazards. Secondary hazards also are to be shown on the shipping papers. The load still will have single placards for the primary hazard.

Two placards arc used in the following situations:

• “Poison” coupled with “Poison Inhalation Hazard,” or “Poison” coupled with “Keep Away from Food.”
• Any material with the subsidiary hazard of being dangerous when wet will have the primary hazard placard plus a “Dangerous When Wet” placard.
• Uranium hexafluoride will be placarded as both radioactive and corrosive when the quantity is greater than 1,001 pounds.

The metric system replaces the U.S. system. Kilograms (kg) replace pounds and liters replace gallons, changes that bring the United States in line with the rest of the world. This creates minor changes in existing regulations. The “1,000-pound rule” (for use of the dangerous placard), for example, now becomes the “1,001pound rule” (454 kg). Most of the weights and sizes have been modified in a similar way.

These changes already have become effective; voluntary compliance with some portions of the regulation began January 1, 1991. Most of the provisions will be enforced completely by October 1, 1993. The delayed enforcement date provides a transition period to allow shippers to understand the regulations and deplete stocks of old labels and placards *