[Header] PHMSA - U.S. Department of Transportation - Pipeline and Hazardous materials Safety Adminis
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This page contains a dynamic list of Hazmat-related terms which also appear in the PHMSA glossary.

Association of American Railroads[more]
Acceptable Level of Risk
for regulations and special permits is established by consideration of risk, cost/benefit and public comments. Relative or comparative risk analysis is most often used where quantitative risk analysis is not practical or justified. Public participation is important in a risk analysis process, not only for enhancing the public's understanding of the risks associated with hazardous materials transportation, but also for insuring that the point of view of all major segments of the...[more]
A device designed to shut off gas flow upon flame failure, pilot outage, control impulse, overpressure, or underpressure without a person being physically at the location. Valve actuators on mainline transmission systems are primarly operated by pushing a button at a control station.[more]
Anodeless riser
A steel casing with a plastic pipe inside. The plastic pipe inside the steel casing is the service line carrying gas to the customer meter.[more]
American Society for Non-destructive Testing [more]
Bureau of Transportation Statistics[more]
Bulk Packaging

A bulk packaging is a packaging, other than a vessel or a barge, with (1) a maximum capacity greater than 450 liters (119 gallons) as a receptacle for a liquid; (2) a maximum net mass greater than 400 kilograms (882 pounds) and a maximum capacity greater than 450 liters (119 gallons) as a receptacle for a solid; or (3) a water capacity greater than 454 kilograms (1000 pounds) as a receptacle for a gas.

The distinction between bulk and non-bulk packagings is important in determining...[more]

Bulk Packaging
A packaging (transport vehicle or freight container) in which hazardous materials are loaded with no intermediate form of containment, when the internal volume is greater than:[more]
Calendar Year

Although the registration year extends from July 1 of a year through June 30 of the following year, a calendar year is used to report activity in item 9 of the registration statement, "Prior-Year Survey Information." This calendar year is the twelve-month period (January 1 through December 31) immediately preceding the beginning date of the registration year (or years) for which you are filing the registration statement. You are asked to supply information on your activities in calendar year...[more]

Capital Improvement
An expenditure for a physical improvement to an existing capital asset such as additions and major alterations that are intended to improve performance or increase useful life. [more]
Product, including its packaging.[more]
Cargo Tank
A bulk packaging that is loaded or unloaded without being removed from the motor vehicle. (The tank may or may not be permanently attached to the motor vehicle).[more]
Code of Federal Regulations [more]
Chart 11
DOT’s Hazardous Materials Marking, Labeling and Placarding Guide.[more]
Relates to possible interactions between a material and (1) its container, or (2) other products that may be loaded or transported together.[more]
PHMSA uses risk management to prioritize compliance activity and address the risk associated with non-compliance. PHMSA places greater compliance emphasis on materials and packagings associated with materials presenting high hazard to the public such as poisons and flammable gases, explosives, and poison inhalation hazard liquids. When packagings are found in non-compliance, risk and benefit/cost assessments are used to determine if an appropriate course of action, such as recall, down-rating or...[more]
Two or more ingredients that are chemically united.[more]
Compressed Gas
Material or mixture meeting criteria in § 173.115(b), (absolute pressure of 280 kPa [41 psia]) at 20°C [68° F] or greater).[more]
is the direct effect of an event, incident, or accident. It is expressed as a health effect (e.g., death, injury, exposure), property loss, environmental effect, evacuation, or quantity spilled. [more]
Sequentially lists the location of each rail car in a train. May serve as the shipping paper if the consist has all the information required by the USDOT.[more]
Canadian Standards Association[more]
Dangerous Goods
International term for hazardous materials.[more]
Docket Management System (historical system used by DOT prior to the Federal Docket Management System (FDMS)). [more]
Completed forms required to accompany hazardous materials. For example, shipping papers, certificates, emergency response information, or manifests.[more]
U.S. Department of Transportation[more]
Emergency Preparedness and Response
Should an incident occur, PHMSA's hazardous materials program includes elements to mitigate the consequences of a release. PHMSA publishes and distributes to first responders an Emergency Response Guidebook to provide guidance on hazards, emergency actions and protective action decision factors and distances. This information is also tailored to reflect the risk of each material. To support emergency preparedness and response planners at the State and local levels, PHMSA, the Federal Emergency...[more]
Emergency Response Information
Information that can be used in the mitigation of an incident involving hazardous materials.[more]
Etiologic Agent
See Infectious Substance.[more]
Midwest Energy Assocaition (MEA)/Energy Training Network (ETN)[more]
Relief from certain HM regulations; applies to everyone.[more]
Specific USDOT-written relief from certain HM Regulations, for shippers, carriers, or manufacturers; 2 year limit but may be renewed. (Part 107, Subpart B of 49 CFR)[more]
The term "farmer" means a person engaged in the production or raising of crops, poultry, or livestock.[more]
Federal Docket Management System. This system houses current dockets.[more]
Federal Energy Regulatory Commission[more]
Flash Point
The minimum temperature at which a substance gives off flammable vapor(s). Substance will ignite when coming in contact with a spark or flame.[more]
Freedom of Information Act[more]
A material that is prohibited from being offered or accepted for transportation. This prohibition does not apply if these materials are: [more]
Used as both Federal Register and Final Rule[more]
Full-time Equivalent[more]
Gneral Accountability Office (formerly General Accounting Office)[more]
An EPA term used for a hazardous waste producer and/or shipper.[more]
Government Printing Office[more]
Planning and training grants to deal with hazardous materials emergencies.[more]
Gross Weight
Total weight of packaging, including its contents.[more]
is the inherent characteristic of a material, condition, or activity that has the potential to cause harm to people, property, or the environment. [more]
Hazard Analysis
is the identification of material properties, system elements, or events that lead to harm or loss. The term hazard analysis may also include evaluation of consequences from an event or incident. [more]
Hazard Class
A group of hazardous materials that share dangerous characteristics. The USDOT has identified nine hazard classes based on the dangers posed in transportation.[more]
Hazard Division
A means of sub-dividing similar hazardous materials which require different hazard communications.[more]
Hazardous Material
A substance or material capable of posing an unreasonable risk to health, safety, or property when transported in commerce.[more]
Hazardous Substance
A material listed in Appendix A to § 172.101 and the quantity in one package equals or exceeds the reportable quantity (RQ). Material may be in solution or mixture. This definition does not apply to petroleum (lubricants or fuel) products. [more]
Hazardous Waste
Any material that is subject to the Hazardous Waste Manifest requirements of the EPA. Refer to 40 CFR Part 262.[more]
Hazardous Waste Manifest
A specific shipping document required by the USDOT and the EPA for hazardous waste shipments. Also referred to as the Uniform Hazardous Waste Manifest (UHWM). If all USDOT requirements [i.e., the basic description (proper shipping name, hazard class/division, ID No., and packing group) are entered on the UHWM, the manifest may be used as a shipping paper. (49 CFR § 172.205)[more]
Hazmat Employee
A person who is employed by a hazardous materials employer and directly affects hazardous materials (hazmat) transportation safety.[more]
Hazmat Employer
A person whose employee(s) perform the following functions:
  • transport hazardous materials (hazmat) in commerce;
  • cause hazmat to be transported or shipped in commerce; or
  • represent, mark, certify, sell, offer, recondition,
  • test, repair, or modify packagings as qualified for use in the transportation of hazmat.

The term "hazmat employer" also includes any department, agency, or instrumentality of the United States, a State, a political...[more]

Highway Route Controlled Quantity
The criteria for determining whether a shipment of radioactive material is a "highway route controlled quantity" are found in 49 CFR 173.403, which further references 49 CFR 173.435. Please note that any shipment of a "highway route controlled quantity" of a radioactive material, whether by highway, rail, air, or water, subjects the offeror and carrier to the registration requirement. If you think you are an offeror or carrier of highway route controlled quantities, please review the defining...[more]
Identification Number (ID No.)
The UN or NA “four-digit number” assigned to hazardous materials, i.e., UN 1203. ID numbers are listed in Col. 4 of the HMT. Used for identification and emergency response.[more]
Office of the Inspector General (also referred to as "OIG"), commonly the office of any Agency which performs these duties. In most documents presented here, assume the Department of Transportation OIG unless otherwise stated.[more]
Refers to the placement of required additional entries on the shipping paper. Usually placed after the complete description for a hazardous material. May be any format, as long as it is clearly part of the entry.[more]
Unintentional release of hazardous material(s).[more]
Infectious Substance
Living microorganism or its toxin which may cause severe, disabling or fatal disease. Term synonymous with Etiologic Agent. (49 CFR, § 173.134)[more]
Information is critical to the effective use and application of hazard/risk analyses. PHMSA has improved the information/data bases used to determine which risks in the transportation of hazardous materials appear to be the greatest, and to identify corrective actions needed to address the major contributors to those risks.[more]
Irritating Material
A liquid or solid substance. Upon contact with fire or air, the material gives off dangerous or intensely irritating fumes. [more]
International Standards Organization[more]
Hazard class identifiers required on hazardous materials packaging; 100 mm diamond shaped (square-on-point); identify hazard class by symbol, color and sometimes, by name.[more]
is expressed as either a frequency or a probability. Frequency is a measure of the rate at which events occur over time (e.g., events/year, incidents/year, deaths/year, etc.). Probability is a measure of the rate of a possible event expressed as a fraction of the total number of events (e.g., one-in-a-million, 1/1,000,000, or 1X10-3). [more]
Limited Quantity (Ltd. Qty.)
The amount of material for which there is a specific labeling or packaging exception.[more]
Marine Pollutant
Hazardous material which is: [more]
Information required to be placed on the outside of the shipping container; may include one or more of the following: [more]
Midwest Energy Assocaition (MEA)/Energy Training Network (ETN)[more]
Measures to prevent, or lessen the results of a release of hazardous materials.[more]
A material composed of one or more compounds.[more]
Modes of Transportation
The four modes of transportation that are covered under the Hazardous Materials Regulations, including the registration requirement, are highway, rail, air, and water. Highway transportation includes all interstate, intrastate, and foreign shipments that meet the registration criteria and are not specifically excepted by regulation. Water transportation does not include hazardous materials loaded or carried on board a vessel without benefit of containers or labels and received and handled by the...[more]
National Association of Corrosion Engineers[more]
National Association of Regulatory Utility Commissioners[more]
National Center for Construction Education and Research[more]
National Fire Protection Association[more]
National Institue of Standards and Technology[more]
Notice of Inquiry[more]
Not-for-Profit Organization
A Not-for-Profit Organization is an organization exempt from taxation under 26 U.S.C. 501(a), which exempts organizations described in subsection (c) or (d), unless the exemption is denied under sections 502 or 503. This category of registrant was first established for the 2003-2004 registration year. Not-for-profit organizations registering for years before 2003-2004 must pay the fee appropriate to the SBA size category (small or not-small) according to the SBA size standard established for the...[more]
Notice of Proposed Rule Making[more]
National Transportation Safety Board[more]
Office of the Federal Register[more]
Office of the Inspector General (also referred to as "IG"), commonly the office of any Agency which performs these duties. In most documents presented here, assume the Department of Transportation OIG unless otherwise stated.[more]
Office of Management and Budget[more]
OSHA (Act)
Occupational Safety and Health Act[more]
OSHA (Administration)
Occupational Safety and Health Administration[more]
Communication of regulatory requirements and changes to the general public and industry is a critical area of risk management. Clear, consistent information dissemination is a top priority with PHMSA. [more]
Public Law[more]
A person is defined by federal hazardous material law as including an individual, firm, copartnership, corporation, company, association, joint-stock association, including any trustee, receiver, assignee, or similar representative thereof, or government, Indian tribe, or agency or instrumentality of any government or Indian tribe when it offers hazardous materials for transportation in commerce or transports hazardous materials to further a commercial enterprise.[more]
Person who Offers or Offeror
A person who offers or offeror is any person who performs or is responsible for performing any pre-transportation function required by the hazardous materials regulations or who tenders or makes the hazardous material available to a carrier for transportation in commerce.[more]
Pre-Transportation Functions

A pre-transportation function is any function specified in the hazardous materials regulations that is required to assure the safe transportation of a hazardous material in commerce, including but not limited to:

  1. determining the hazard class of a hazardous material;
  2. selecting a hazardous materials packaging;
  3. filling a hazardous materials packaging, including a bulk packaging;
  4. securing a closure on a filled or partially filled hazardous materials...[more]
Quantitative Risk Analysis
incorporates numerical estimates of frequency or probability and consequence. In practice a sophisticated analysis of risk requires extensive data which are expensive to acquire or often unavailable. Fortunately few decisions require sophisticated quantification of both frequency and consequences. [more]
Regulatory Standards
The hazardous material regulatory system is a risk management system that is prevention oriented and focused on identifying a hazard and reducing the probability and quantity of a hazardous material release. Hazardous materials are categorized by hazard analysis and experience into hazard classes and packing groups. The regulations require each shipper to classify a material in accordance with these hazard classes and packing groups; the process of classifying a hazardous material is itself a...[more]
Relative Risk Analysis
means that a risk is evaluated in comparison to another risk. The type of risk analysis used should be appropriate for the available data and to the exposure, frequency and severity of potential loss. [more]
the combination of the likelihood and the consequence of a specified hazard being realized. It is a measure of harm or loss associated with an activity. [more]
Risk Analysis
is the study of risk in order to understand and quantify risk so it can be managed. [more]
Risk Assessment or Risk Characterization
is determination of risk context and acceptability, often by comparison to similar risks. [more]
Risk Management
is the systematic application of policies, practices, and resources to the assessment and control of risk affecting human health and safety and the environment. Hazard, risk, and cost/benefit analysis are used to support development of risk reduction options, program objectives, and prioritization of issues and resources. A critical role of the safety regulator is to identify activities involving significant risk and to establish an acceptable level of risk. Near zero risk can be very costly and...[more]
Research and Innovative Technology Administration (of the U.S. Department of Transportation)[more]
Serious Incident

Starting with reporting on 2002 incidents, PHMSA defines "serious incidents" as incidents that involve:

  • a fatality or major injury caused by the release of a hazardous material,
  • the evacuation of 25 or more persons as a result of release of a hazardous material or exposure to fire,
  • a release or exposure to fire which results in the closure of a major transportation artery,
  • the alteration of an aircraft flight plan or operation,
  • the...[more]
The term "shipment" as used in the registration regulations means the offering or loading of hazardous material at one loading facility using one transport vehicle, or the transport of that transport vehicle (see 49 CFR 107.601(c)).[more]
Small Business

A person is a "small business" if its size does not exceed the size standard established by the U.S. Small Business Administration (SBA) in 13 CFR 121 for the primary commercial activity of the person (company).

Since the 2000-2001 registration year, the amount of the annual registration fee has depended on whether the registering company meets the SBA size standard for a small business. The SBA assigns a size standard, which is expressed, with a few exceptions, either as the number...[more]

Supplemental Notice of Proposed Rulemaking[more]
Special Permits to the Hazardous Materials Regulations
Congress in the Hazardous Materials Transportation Act of 1974, created a risk management program that can authorize alternative regulations. The purpose of these alternative regulations -- special permits -- is to facilitate the implementation of more efficient methods and new technologies that provide a level of safety at least equal to that provided by the regulations. The procedural regulations governing PHMSA's special permits program, published under section 107.103 of Title 49 of the Code...[more]
Training (Hazmat)
A systematic program (i.e., consistent approach, testing, and documentation) that ensures that a hazardous materials (hazmat) employee has knowledge of hazardous materials and the Hazardous Materials Regulations (HMR), and can perform assigned hazmat functions properly. Refer to § 172.700(b) through § 172.704 of the regulations. [more]

Transportation means the movement of property and loading, unloading, or storage incidental to the movement (49 U.S.C. 5102(13)).

Transportation functions are definedat 49 CFR 171.1(c)

Transportation Safety Institute[more]
United States Code[more]