
The EPA has determined that certain solid wastes are hazardous wastes if they may cause an increase in mortality or illness or pose substantial hazard to human health or the environment when improperly managed. A waste is considered hazardous if it: 1.) is listed on one of the lists of hazardous wastes published by EPA in 40 CFR Part 261, Subpart D; or 2.) exhibits one or more of the four hazardous characteristics defined in 40 CFR Part 261, Subpart C. Listed and characteristic hazardous wastes are identified using EPA codes consisting of one letter followed by three digits. Some states may use additional codes for state-unique hazardous waste streams. For example, the hazardous waste code for used oil in Massachusetts is MA98. For listed wastes, the first letter in the code corresponds to the common list name (e.g., "F-List"). The first letter in the codes of characteristic wastes is D. Generators are required by law to identify their hazardous wastes with all applicable codes.
To determine if a waste is a regulated hazardous waste, the generator needs to accomplish three things. First, determine whether the waste fits within the definition of "solid waste" and, if so, whether the waste is excluded from regulation under 40 CFR § 261.4. Next, they need to examine whether the waste is listed as a hazardous waste in 40 CFR Part 261, Subpart D. Finally, the generator needs to consider whether the waste exhibits one or more of the hazardous characteristics identified in 40 CFR Part 261, Subpart C. In making these determinations, generators may use either analytical testing or their knowledge regarding the process that generates the waste. Wastes such as outdated raw materials may not require testing since knowledge of the chemicals' origins and characteristics may be applied in the determination. Material safety data sheets (MSDSs) are often useful for this purpose.

There are four primary lists of hazardous wastes. To determine if a waste is listed, one must have knowledge of the waste's origin. The lists are described briefly below, but complete copies of the hazardous waste lists are included in 40 CFR Part 261.
EPA has identified four hazardous waste characteristics: ignitability, corrosivity, reactivity and toxicity. Generators may use testing or knowledge to determine if their wastes exhibit one or more of the characteristics.
When hazardous waste is accumulating at the point where it is initially generated and is under the control of the process operator generating that waste, it is considered to be in a "satellite accumulation area" and is subject to minimal regulatory requirements (40 CFR §262.34(c)). Specifically, hazardous waste containers must remain closed except when adding waste; containers must be marked with the words "hazardous waste" or other words that identify the containers' contents; containers must be in good condition and compatible with the wastes they contain; and no more than 55 gal of hazardous waste or one quart of acutely hazardous waste may be stored at each satellite accumulation area.
Hazardous Waste in a Designated Accumulation Area
Once hazardous waste leaves the satellite accumulation area and enters a different location, referred to here as an accumulation area, it is subject to more stringent management standards. When waste leaves the satellite accumulation area, "the clock starts," and from this date, the waste must be shipped off-site to a permitted hazardous waste treatment, storage or disposal facility (TSDF) within 90, 180 or 270 days, depending on the generator's status (e.g., CESQG, SQG, or LQG) and distance from the TSDF (40 CFR § 262.34).
In the accumulation area, all hazardous waste containers must be clearly marked with the date they entered the area. All containers must be clearly marked "hazardous waste." Emergency equipment must be maintained at the accumulation area and periodically tested to ensure it is in working order (e.g., communications device or alarm system, fire extinguishers, spill control equipment, etc.). Waste containers must be arranged in the accumulation area so that there is adequate aisle space to allow for the flow of emergency personnel and equipment. Incompatible wastes must be separated to the extent possible using distance, berms or containment pans. The accumulation area must be inspected weekly for leaks and deterioration, and to ensure adequate spill response materials are on-hand.
Prior to off-site disposal, careful waste segregation is important for both safety and economic reasons. For example, if methylene chloride waste is mixed with a B-side polyol blend, then more hazardous waste is generated and the cost of disposal will escalate because of the chlorine content, which decreases the opportunity for fuel blending the polyol or recycling the methylene chloride. Fuel blending and recycling generally are less expensive options and can be more responsible stewardship than conventional hazardous waste incineration. Potential liability arises from the disposal of all chemical wastes, most particularly hazardous waste. Under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA or "Superfund"), a person who arranges for the disposal or treatment, or transportation for disposal or treatment, of a hazardous substance can be held liable for any future remedial costs associated with those substances. Hazardous wastes qualify as hazardous substances under CERCLA, as do MDI, TDI and other products used in the polyurethane industry. In order to limit potential liability, processors should ensure that all wastes are disposed, treated and transported properly by licensed, reputable firms.
For example, excess, pure TDI waste reacted with a polyol would form an inert polyurethane that may be regulated as U223 hazardous waste. However, excess MDI waste reacted with polyol would not result in a regulated material because MDI is not a U-listed chemical. Although some treatment of hazardous wastes without a permit is allowed by most states, processors are cautioned to check with their state regulators before treating any hazardous waste.
Keep in mind that permits for treatment are only required for RCRA "hazardous wastes" and state-regulated waste streams. Processors may treat wastes that are not regulated as hazardous. In many cases, excess A-side (isocyanate) and B-side (polyol) formulations may be reacted to make non-hazardous solids that may be disposed of with regular trash. Regardless, check with the waste transporter and disposal facility before mixing any non-hazardous waste streams together or with the regular plant trash.
From Guidelines for the Responsible Disposal of Wastes and Containers from Polyurethane Processing, the Alliance for the Polyurethanes Industry. For more information, phone (703) 741-5656 or visit http://www.polyurethane.org.
2. http://www.epa.gov/epaoswer/osw, Links to information concerning permits, storage, disposal, recycling, and identification of hazardous waste and EPA regulations.
3. http://www.epa.gov/rcraonline, RCRA Online - enables search for questions/answers; guidance documents on all aspects of the EPA's hazardous waste regulations.
4. http://www.atsdr.cdc.gov, Agency for Toxic Substances and Disease Registry - health effects and minimum risk levels of hazardous chemicals.
5. http://www.epa.gov/estpages/wasthazardouswaste.html, Contains links to hazardous waste and RCRA information within EPA.
6. http://www.epa.gov/epaoswer/osw/regions.htm, Link to regional EPA and state hazardous waste offices.
7. http://www.osha.gov/SLTC/hazardouswaste, Safety and health information for hazardous waste handlers (PPE, training, etc.).
8. http://hazmat.dot.gov, DOT HazMat site - information regarding regulations governing the transportation of hazardous materials.