From the archives of the Enforcement and Compliance Listserv for Hazardous Waste Generators

Labels and Marking | Container Management

Labels and Markings

July 30, 2008 - The term "label", when referring to hazardous waste containers, means the diamond-shaped hazmat identification used to convey the danger associated with the waste. Some examples of labels are corrosive, ignitable, and poison. Labels must appear in their entirety at the proper size, print style, border, and color. The term "marking" refers to important information on the container such as the United Nations substance number or North American identification number (the four digit number following UN or NA that identifies the hazardous chemical or class of hazardous material), descriptive name (including the term "Waste" when it is a hazardous waste), technical name, and shipper's name and address. See the downloadable version of the U.S. Department of Transportation's List of Hazardous Materials containing proper shipping names, UN numbers and more for almost 3,500 entries. Although labeling and marking are often used interchangeably, be certain when you read the regulations you know which one they are referring to. As an illustration of how this can be confusing, the item often referred to as a "hazardous waste label" is really a marking under the U.S. Department of Transportation and hazardous waste regulations. June 30, 2008

May 31, 2007- Label Placement

Labels are used to identify the hazard class of material in containers and packages offered for transport. Because the labels are used to communicate important information, it is vital that they are easy to locate. In general, to meet U.S. Department of Transportation requirements, labels must be: on a surface other than the bottom of the package AND be located near and on the same surface of the package as the marking of the proper shipping name. If your hazardous waste requires multiple hazard labels, then they must be placed within 6 inches (150 mm) of one another. The primary hazard label is listed first in column 6 of the 49 CFR 172.101 Hazardous Materials Table, and any subsidiary label (if necessary) is listed next.

Mixed and Consolidated Packaging

If your business consolidates shipments - puts multiple, compatible hazardous wastes together for storage or transport - then you must label the packaging, outside container or overpack with every hazard class of the waste it holds. As always, never put incompatible hazardous waste together. You may find a list of incompatible hazardous wastes in Appendix V of CFR 265.

Duplicate labeling is required when:

  • The package or overpack has a volume of 1.8 cubic meters (64 cubic feet or approximately 480 gallons).
  • Any non-bulk package containing radioactive material.
  • Each DOT 106 or 110 multi-unit tank car tank (display on each end).
  • A portable tank of less than 3,785 L (1,000 gallons) capacity.
  • Freight containers or aircraft unit load devices having a volume of 1.8 cubic meters (64 cubic feet or approximately 480 gallons) but less than 18 cubic meters (640 cubic feet).

If your business uses these types of containers for hazardous waste storage or transport, labels must be displayed on at least two sides of the container.

Marking Satellite Containers

You have several options when marking hazardous waste stored in satellite accumulation areas. According to 10 CSR 25-5.262(2)(C)3, hazardous waste containers in satellite accumulation areas must be marked with "Hazardous Waste," the EPA waste code, shipping description, description of contents ("waste toluene") or other words that identify the contents of the containers. Also, unlike hazardous waste in 90 or 180-day storage, hazardous waste in satellite accumulation areas does NOT need to be labeled or marked according to U.S. Department of Transportation regulations.

Labeling or Marking Universal Waste

As with satellite containers, universal waste also has labeling options:

  • For mercury switches, in Missouri the label should read "Universal Waste-Mercury Switch(es)", or "Waste Mercury Switch(es)" or "Used Mercury Switch(es)".
  • For batteries, the label should read "Universal Waste-Battery(ies)" or "Waste Battery(ies)" or "Used Battery(ies)".
  • For thermostats, the label should read "Universal Waste-Mercury Thermostat(s)", "Waste Mercury Thermostat(s)" or "Used Mercury Thermostat(s)".
  • For lamps, the label should read "Universal Waste-Lamp(s)", "Waste Lamp(s)" or "Used Mercury Lamp(s)".
  • For pesticides, the label should read "Universal Waste-Pesticide(s)" or "Waste Pesticide(s)".

Remember, hazardous waste pesticides may only be managed as a universal waste as long as they are sent to a Missouri approved universal waste pesticide collection program, to a Certified Resource Recovery Facility or to a Universal Waste Destination Facility.

April 23, 2007 - Labeling and Marking

Throughout the next few listservs we will discuss labeling and marking requirements for your hazardous waste. Small and Large Quantity Generators that store hazardous waste in containers must place and maintain the following information on each container from the time waste is first placed in the container:

  • Markings - container must display the wording as it appears below:

"HAZARDOUS WASTE - Federal Law Prohibits Improper Disposal. If found, contact the nearest police or public safety authority or the U.S. Environmental Protection Agency. Generator's Name and Address: (fill in your company's name and complete address including city and state) Manifest Document: (fill in manifest document number when the container is prepared for shipment off-site)"

  • Accumulation Date - the day, month and year that you first placed waste in the container.
  • Labeling - In Missouri, each container must be labeled with the appropriate U.S. Department of Transportation hazardous material warning label commonly known as the U.S. Department of Transportation (US DOT) diamond sticker. Examples include "flammable liquid," "corrosive," and "poison".

Labels and markings must be durable. Labels must not be obscured by other markings or covered by attachments. If reusing a container, make sure all old labels or markings are removed or painted over to avoid confusion. Move, or orient, containers so that both employees and inspectors can see all important information. This helps ensure that hazardous waste is accounted for and is not stored in excess of the time limit.

If the accumulation date on the container is handwritten, be certain that it is legible and clear. Be consistent in the date format that you use. Pick one format (e.g. month/day/year or year/month/day) and stick with it.

For more information on the U.S. DOT. Chart 12 Hazardous Materials Marking Labeling and Placarding Guide, view page 63 of the department's Hazardous Waste Management Handbook for Small Quantity Generators. Check every hazardous waste container that you have in storage and make sure that all the proper information is present and visible. Proper labels and markings help make sure your employees, emergency responders, and waste handlers, manage the waste safely and appropriately.  Please review the Hazardous Waste Generator Archive Satellite Accumulation for more information on marking and labeling satellite accumulation containers.

Container Management

July 2010 - Department inspectors use the following five part test to determine if a hazardous waste container is appropriately "closed" according to law and regulation.  Closed containers must:

  • Minimize emissions of volatiles. 
  • Help protect ignitable and reactive wastes from sources of ignition and reaction.
  • Help prevent spills.
  • Reduce the potential for mixing of incompatibles.
  • Reduce the potential for direct contact between employees and hazardous waste.

If you business believes that it has a particular situation where a hazardous waste container in either satellite accumulation or in storage would not be able to meet the five part test but should be allowed, we suggest you contact the department to discuss the specifics. In some situations, usually involving safety issues, the department has been able to accept alternative methods for closing a container. 

  • When inspecting your closed containers look for the following common problems:
  • Ball closure valve between the funnel and the drum not in place or not closed;
  • Funnels with lids not latched;
  • Funnels not air tight due to damage or lack of gasket or seal;
  • Funnels not secured into the container;
  • Bungs not secured in drums;
  • Snap rings not secured;
  • Ring top locking mechanisms not engaged;
  • Plastic liner of containers not closed inside cardboard boxes;
  • Not following manufacturers' specifications for closing containers.

June 2010 - Closed Containers - Solids and Semi-Solids

As with containers storing liquid hazardous waste, containers storing any hazardous waste must be closed at all times except when adding or removing wastes. But when managing a solid or semi-solid hazardous waste, what does closed mean? Keep in mind the following closed container requirements: minimizing emissions of volatiles, helping protect ignitable and reactive wastes from sources of ignition and reaction, helping to prevent spills, reducing the potential for mixing of incompatibles, and reducing the potential for direct contact between employees and hazardous waste.

Again, we look at the intent of the law to discern what closed would mean in certain situations. If your semi-solid is a filter containing a solvent, then the container must be vapor tight and spill proof if the filters contain any free liquids. A volatile solid must be managed with the highest level of care to ensure vapors do not escape that could cause a fire, explosion, or negatively effect human health or the environment.

Similarly, if your hazardous waste solid is granular or a dust, a high degree of care must be used when storing this type of waste so that no releases occur. This means that the tight fitting lid for the container may not cause a release when opened and completely filling any container to capacity is typically not an option. For instance, a granular pesticide that is toxic should not be stored in a foot pedal operated container due to the potential release of small particles of hazardous waste when opened. When storing granular or dust type hazardous wastes in Gaylord boxes or roll-off containers, filling these containers to absolute capacity may cause a release and should be avoided. Always use the proper storage container for your material and always follow the manufacturer's directions for proper storage.

Be certain when you choosing your container for storage that you are truly familiar with the properties of you waste. A solid hazardous waste could potentially be both toxic for metals and toxic for benzene, making it potentially volatile. Many types of hazardous wastes have mixed hazards. Therefore, any container used must:

  • Minimize emissions of volatiles.
  • Help protect ignitable and reactive wastes from ignition and reactive sources.
  • Help prevent spills.
  • Reduce the potential for missing of incompatibles.
  • Reduce the potential for direct contact between employees and the hazardous waste.

For unbroken fluorescent light bulbs they may be stored in the cardboard box that the bulbs arrived in, so long as the box is closed when not adding or removing bulbs. If the bulbs did not come in cardboard packaging, you may use an alternative, protective container so long as the bulbs are not broken during storage.

May 2011 - Closed Containers
Over the next few months we will discuss closed containers. Containers of hazardous waste must be closed at all times, except when adding or removing hazardous waste.  Hazardous waste generators often consider the closed container requirements difficult to meet due to the variation of wastes, necessary employee training, and day to day operations of a facility. But the closed container requirements were developed using the following reasoning:

  • Minimize emissions of volatiles.
  • Help protect ignitable and reactive wastes from sources of ignition and reaction.
  • Help prevent spills.
  • Reduce the potential for mixing of incompatibles, and reduce the potential for direct contact between employees and hazardous waste.

Keep these reasons in mind when evaluating your closed hazardous waste containers. These standards apply to all hazardous waste; however, there are many methods or ways to meet the above standard.
Liquid hazardous waste
Liquid hazardous waste poses four main problems.  The risk of

  • Spills. 
  • Leaks. 
  • Inhalation injuries. 
  • The buildup of vapors. 

Liquid hazardous waste containers are closed when all openings or lids are properly and securely affixed to the container. In practice this means there is no release of volatile or organic emissions and no chance of spillage if the container is tipped over. A closed container can be achieved in many ways and it is the responsibility of the generator to assure that the closed standard is met. Generators may use rings that are either clamped or bolted, snap rings to secure lids to a container, properly secured bungs using the required pressure wrench according to manufacturer specifications, spring closed funnels that are fitted with functioning sealing gaskets, funnels with one-way valves that retain emissions or vapors or an alternate locking mechanism that meets the requirements. 

Examples of what would not meet the closed container standard include but are not limited to: lids placed on a drum but not secured, funnels that neither manually or spring close properly, bungs placed in the drum but not tight sealed, funnels whose sealing gaskets have aged or worn and no longer perform the function of sealing in liquids and vapors, caps not tightened, and improperly fitting seals.

 Although Conditionally Exempt Small Quantity Generators, or CESQGs, do not have to follow the closed container requirements, many CESQGs do find these standards helpful when managing their hazardous waste.  CESQGs are responsible for managing their hazardous wastes in a way that does not threaten human health or the environment or create a public nuisance. If volatile emissions are allowed to escape from hazardous waste containers and ignite or adversely affect employees, then a CESQG would be in violation of this most basic standard.   As you are aware, CESQG are not allowed to throw hazardous waste into the sanitary trash. 

July 30, 2008 - Proper container management is always a high priority for hazardous waste generators. This month's listserv is devoted to explaining common container requirements.

Always start with a container that's in good condition. Good condition means no holes or punctures; it also means no rusting, dents, or bulges in the seams. Those types of defects could weaken the container and allow a hazardous waste release. If you purchase reconditioned containers be sure to inspect the containers when you receive them. Careful inspection upon delivery will prevent you and your employees from using a damaged or substandard container. Don't forget, the lid and closure mechanism must be in good working condition as well.

The next thing to consider is compatibility of wastes and containers. Hazardous waste must be compatible with the container in which it is stored. There are a wide range of container choices available for your business. Here are some guidelines to consider when purchasing containers:

  • Fiber-board drums or gaylord boxes can be used for some solid hazardous wastes and are an economical choice. Don't forget to consider your hazardous waste's properties if it becomes humid. Certain solids quickly absorb moisture, making them unsuitable for storage in a fiber-board container without an inner liner. Some liquids may be suitable for storage in lined fiber-board containers.
  • Steel drums: Corrosive hazardous wastes must never be stored in steel drums. Corrosive hazardous waste will erode steel containers and cause their failure. Containers weaken by corrosive hazardous waste are also easily damaged when moved or emptied.
  • Plastic or polyethylene drums: Hazardous waste solvents or strong oxidizing acids that will dissolve polyethylene must never be stored in plastic or polyethylene drums. These hazardous wastes will dissolve the container resulting in a release of the hazardous waste.

Some Material Safety Data Sheets provide recommendations for what type of container to use to store your hazardous waste. Your hazardous waste transporter may also have advice on waste and container compatibility.

Container size is also important. Any non-exempt person that generates or accumulates (stores) 100 kilograms, or 220 pounds, or more of non-acute hazardous waste in Missouri must comply with more stringent regulations than a conditionally exempt small quantity generator that generates and accumulates less than 100 kilograms or 220 pounds. If your business only generates a conditionally exempt amount of hazardous waste but waits several months for it to accumulate so you can ship a 55-gallon drum of hazardous waste, then this shipment will likely be large enough to cause your business to be regulated as a small quantity generator. On the other hand, if your business uses a smaller container that holds less than 220 pounds and never stores more than 220 pounds, you will remain a conditionally exempt small quantity generator.

Hazardous waste generators in Missouri must follow U.S. Department of Transportation packaging requirements for hazardous waste during the entire onsite storage period. U.S. DOT regulations on packaging can be found at 49 Code of Federal Regulations parts 173, 178 and 179.

Aug. 29, 2007 - What About Container Weight?

Question: When determining the weight of hazardous waste to be shipped, do you include the weight of the container? Or just the waste inside the container?

Answer: If you are trying to calculate your hazardous waste generator status, then the container itself is not considered a hazardous waste so it's weight does not need to be counted towards your hazardous waste generation level (e.g. Large, Small or Conditionally Exempt). Your business may track the weight of the hazardous waste itself, however you should realize that transporters typically include the entire weight of the item, packaging and all, so that may be reflected on the manifest. See EPA's guidance on this subject.

If you subtract container weight from the entire weight transported to track you hazardous waste generation rate, be aware that any new container you purchase may not weigh the same amount as your current containers. For instance, steel drums made today usually weigh less than their predecessors but still meet the same strict U.S. Department of Transportation performance requirements for transport due to improved design. If you change containers, be sure to change your calculation for determining the weight of the hazardous waste in the container.

If you choose to use volume to track your hazardous waste generation, you must know the specific gravity of each waste stream to make sure you are managing your waste in accordance with the correct generator level. You can use volume and specific gravity to calculate the weight of the waste. First, multiply the specific gravity of your liquid by the density of water (8.33 lbs/gallon) to find the density of the liquid. Then multiply the density of the liquid by the volume of the liquid to equal the weight of the waste. For instance, a 55-gallon container of toluene has a specific gravity of 0.866. Multiply 0.866 by the density of water, 8.33 lbs/gallon. The resulting density is 7.21 lbs/gallon. Multiple 7.21 lbs/gallon by 55 gallons and the result is the weight of the toluene in pounds (396.55 pounds). You can usually find the specific gravity on the Material Data Safety Sheet or, if your waste is a mixture, by using knowledge and the specific gravities of the constituents.

If you decide to dispose of a hazardous waste container, then you must make a hazardous waste determination on the container itself. At the time the container is destined for disposal and is determined to be a hazardous waste, then it will count towards your hazardous waste generation level. Often generators of acute wastes choose to dispose of the associated container and thus the entire weight of both the acute hazardous waste and the container would be considered hazardous. For more information on the definition of empty or acute hazardous waste, please review our previous listserv on the subject at

Sept. 28, 2006 - What is a hazardous waste container?

The RCRA hazardous waste regulations define a container as "any portable device in which a material is stored, transported, treated, disposed of, or otherwise handled." The definition is broad enough to cover the many different types of portable devices that may be used to handle hazardous waste, ranging from small test tubes to 55-gallon drums to large tanker trucks.

Hazardous Waste Container Management Requirements:

  • All containers used to hold hazardous waste are required to be in good condition.
  • Containers holding hazardous waste must be closed at all times, except when adding or removing waste.
  • Containers must be clearly marked with the words HAZARDOUS WASTE.
  • Containers must be marked with the date you begin to collect waste in that container. Waste stored must be compatible with its storage container.
  • Incompatible wastes must be stored separately or protected from each other by a dike, berm or wall. For example, you must keep waste alkaline cleaner segregated from spent acid to avoid a bad reaction. Please see our electronic newsletter archive on incompatible chemicals.
  • Containers holding ignitable or reactive waste must be at least 50 feet from the generator's property line or meet alternative requirements.
  • Maintain aisle space between containers to provide easy inspections and movement of personnel and equipment.
  • All containers and container areas must be inspected for leaks or corrosion at least weekly. Inspection records need to be kept for three years following the date of inspection.
  • Areas subject to spills must be inspected daily.
  • In Missouri, hazardous waste must be packaged, labeled and marked per U.S. Department of Transportation regulations the entire time they are in storage.
  • In Missouri, precautions must be taken to prevent accidental ignition or reaction of ignitable or reactive waste. This includes confining smoking and open flame to specially designated locations and hanging "No Smoking" signs near ignitable or reactive waste.

Container Tips - Suggestions for Managing your Containers

  • Let your employees choose the type of closure device that will work best for them.
  • Although stacking drums is allowed, we strongly recommend placing a stabilizing material between drums and stacking no more than two drums high.
  • Hang your weekly inspection log on a clipboard in the storage area. When it is full, file it in your permanent records. Make sure the inspection log includes the employee's name, the date and time of each inspection, his or her observations of each inspection, and the repairs or remedial actions completed.
  • To avoid waste spills from destroying your label, place the label on the side of the container away from the bung. You may also wish to protect labels by applying a thin coat of varnish, covering them with clear packing tape or enclosing them in a plastic pouch designed for that purpose.

Feb. 15, 2006 - Closed containers?

Are your hazardous waste containers closed? Open containers are frequently a compliance issue for hazardous waste generators. According to 40 CFR 265.173(a) "A container holding hazardous waste must always be closed during storage, except when it is necessary to add or remove waste" Properly closed containers benefit you by helping to prevent spills, reducing emissions of volatile wastes, reducing the chance for incompatible chemicals to mix, protecting ignitables or reactive wastes from possible sources of ignition or reaction and preventing contact with employees.

When evaluating whether a container is properly closed it is important to answer these two questions: Is the container vapor tight? and Is the container spill proof? If you can answer yes to both of these questions then you can consider the container closed. Unless adding or removing waste, bungs on drums must always be in place and tightly secured. Lids on other types of containers must be capable of preventing vapors from escaping and spills from occurring. Because some closures can deteriorate over time, it is important to frequently check closure equipment to make sure it continues to be functional. Don't forget that the closure requirements apply to both hazardous waste containers located in storage and in satellite accumulation areas.

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If you need further assistance, please Email or contact the Department of Natural Resources' Hazardous Waste Program at 573-751-7560 or 800-361-4827.

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