Making a Hazardous Waste Determination

Hazardous Waste Program fact sheet
Division of Environmental Quality Director: Leanne Tippett Mosby

This fact sheet introduces some important features of the Missouri Hazardous Waste Management Law and Regulations. Businesses should refer to the appropriate state and federal laws and regulations and review the fact sheet, Does Your Business Generate Hazardous Waste? (Pub117), available on the department's website at, or through the contacts at the end of this guidance document

The Missouri Hazardous Waste Management Regulations require all regulated generators of hazardous waste to determine if their wastes are hazardous. Some businesses recycle or treat their waste at their facility according to certain exemptions in the regulations. However, most Missouri generators rely on other businesses to recycle, treat, store and dispose of their hazardous waste.

What businesses produce hazardous waste?
Most manufacturers, repair businesses, laboratories, retailers, hospitals and cleaning businesses produce some form of hazardous waste. Municipalities and school districts can also be hazardous waste generators.  Some generators are small businesses, such as dry cleaners, auto repair shops, gas stations and exterminators. Some are larger businesses, such as chemical manufacturers, universities, automobile factories and lumber-treating facilities.

What are some examples of hazardous waste?
Hazardous wastes can be liquids, sludges, solids or gases. They can be wastes from manufacturing processes or discarded commercial products. Examples of hazardous waste include used solvents, electroplating chemicals, pesticides, paint, pharmaceuticals and chemicals that can no longer be used and are destined for disposal.  All solid waste generated requires a hazardous waste determination.  Hazardous waste listings and definitions are located in 40 Code of Federal Regulations (CFR) Part 261, Subparts C and D. incorporated and modified by 10 Code of State Regulations (CSR) 25-4,261.

What is hazardous waste?
A hazardous waste is any solid waste that is ignitable, corrosive, reactive (tendency to react or explode), toxic, or listed as a hazardous waste in state or federal regulations. Solid waste can be a solid, liquid or gas and includes the following materials:

How is a hazardous waste determination conducted?
Based on the federal regulations, 40 CFR 262.11- Hazardous Waste Determination. The generator of the waste should determine if the waste is a hazardous waste using the following method:

  1. Determine if the waste is excluded from being a hazardous waste per 10 CSR 25-4.261(2)(A) and 40 CFR 261.4; then
  2. Determine if the waste is listed as a hazardous waste per 10 CSR 25-4.261(2)(D) and 40 CFR 261 subpart D; then
  3. Determine if the waste is a characteristic hazardous waste (i.e. ignitable, corrosive, reactive, or toxic).

Consider the materials used or the processes used to generate the waste. Based on this knowledge, determine the appropriate analysis in accordance with 10 CSR 25-4.261(2)(C) and 40 CFR 261 subpart C. EXAMPLE: Spent Tetrahydrofuran (THF) solvent from a printing process.

Determine if it is excluded as a hazardous waste. Under 40 CFR 261.4 there are no specific exclusions for this spent solvent from a printing process. Determine if the waste is a listed hazardous waste. THF is not a listed hazardous waste. Determine if the waste is a characteristic hazardous waste. The waste is stable in the environment (reactivity) but might catch fire easily (ignitability) and the pH is between 2 and 12.5 (corrosivity). If the virgin material wasn’t pure or may have picked up contaminants in the process , such as metals from the ink, it should be tested for toxic characteristics (toxicity).

Testing for hazardous waste characteristics requires sampling at the point of generation. If the analyses detect any property characteristic of hazardous waste, you must manage the waste as a hazardous waste.

It is very important to understand that hazardous waste remains a hazardous waste when diluted or stabilized, unless it is specifically excluded from the definition of hazardous waste after the process (40 CFR 261.3). You may not dilute hazardous waste solely for the purpose of rendering it non-hazardous unless dilution is part of a hazardous waste treatment process regulated or exempted under 10 CSR 25-7 or 10 CSR 25-9. You may not dispose of regulated hazardous wastes in any sanitary, demolition, utility waste or special waste landfill in Missouri.

The following table lists typical properties of characteristic hazardous waste. This is not a complete listing, but only a guideline to determine if a waste is a characteristic hazardous waste.

A flash point less than 60oC (140oF). Catches fire easily through friction, absorption of moisture or spontaneous chemical changes. Might be a compressed gas or an oxidizer. 

An aqueous solution with a pH<2.0 or pH>12.5.  It is a liquid that corrodes steel more than 6.35 mm per year. 


TCLP, EPA Method 1311, any contaminant listed in Table 1 of 40 CFR 261.24 with a concentration equal to or greater than the listed concentration. Once a waste is determined to be hazardous it must be managed (registered, stored, shipped, disposed) according to Missouri Hazardous Waste Laws and Regulations.

What happens to hazardous wastes in Missouri?
The Missouri Hazardous Waste Management Law, located in the Missouri Revised Statutes, Sections 260.350 to 260.434, RSMo., set up a "cradle-to-grave" system for proper handling of hazardous waste. Hazardous waste is tracked from the time it is created ("cradle") until it is treated or disposed ("grave"). This includes businesses that generate hazardous waste, hazardous waste transporters and the businesses that recycle, treat, store or dispose of hazardous waste.

Hazardous waste transporters pick up the wastes from the waste generators, and take it to a destination facility authorized to recycle, treat, store or dispose of hazardous waste. Only a licensed hazardous waste transporter can legally ship hazardous waste in Missouri. Hazardous waste generators that produce or collect less than 100 kilograms or 220 pounds of hazardous waste each month are allowed to ship their own hazardous waste to an authorized facility if they use their own employees and follow certain regulations. The Missouri Department of Transportation, Motor Carrier Services Unit, now issues Hazardous Waste Transporter Licenses. For more information, visit their website at

All hazardous waste shipped within or into Missouri must reach its destination facility or leave the state within 10 calendar days. A tracking document called the Uniform Hazardous Waste Manifest must accompany all shipments.  A list of hazardous waste transporters currently licensed to transport hazardous waste in Missouri can be found at

Resource Recovery
Hazardous waste resource recovery is reusing or reclaiming hazardous waste or transforming hazardous waste into a new product that is no longer a waste. Reclaiming a hazardous waste involves processing it to recover a usable product. For example, a facility that produces spent solvent during its manufacturing process can distill or filter that solvent to produce a clean solvent. The clean solvent can be used as new product back in the manufacturing process or sold on the open market.  Other wastes that can be used in resource recovery include paints, cathode ray tubes, spent lead-acid batteries and caustics.

Missouri Hazardous Waste Management Law requires certain facilities that perform hazardous waste resource recovery to get a resource recovery certificate. For more information, please review 10 CSR 25-9.020 and the fact sheet, Hazardous Waste Resource Recovery (PUB2091), available on the department's website at, or by calling the department's Hazardous Waste Program at 573-751-3176 or 800-361-4827.

Businesses that have properly registered with the department may store their own generated hazardous wastes for 90 days or 180 days. The storage time allowed is based on the amount of hazardous waste generated. Businesses cannot accept hazardous waste from other locations, even their own affiliates, without a hazardous waste permit

The department authorizes permitted commercial hazardous waste storage facilities to receive hazardous wastes from off-site hazardous waste generators and store it in tanks or containers. By doing this, enough of a specific waste can be collected to make its treatment or disposal more affordable.

Businesses that actively treat hazardous waste in Missouri are required to get a hazardous waste permit. Treatment facilities use a variety of ways to change the character or structure of the waste to make it less hazardous or non-hazardous. Examples of hazardous waste treatment include burning (for destruction or energy recovery), chemically neutralizing, using bacteria to break down the waste (bioremediation) and fuel blending.

There are currently no commercial land disposal facilities in Missouri that have permits to accept hazardous waste from offsite for disposal.  Land disposal is the least preferred method of handling hazardous waste. This form of disposal includes engineered land treatment units, landfills, surface impoundments (ponds) and waste piles. Hazardous waste that is land disposed must be treated to be made less hazardous before it can be disposed.

For More Information

Missouri Department of Natural Resources
Hazardous Waste Program
Compliance & Enforcement Section
P.O. Box 176
Jefferson City, MO 65102-0176
800-361-4827 or 573-751-3553

Or contact your local department regional office: