Incinerators
Hospital/medical/infection waste incinerators (HMIWIs) were formerly used at many U.S. hospitals, healthcare facilities and commercial waste disposal companies to burn infectious wastes and other materials. In time, however, medical incinerators were found to be contributing to health and environmental problems. They were recognized as significant sources of airborne mercury, and the EPA’s 1994 Draft Dioxin Reassessment identified medical waste incineration as the single largest source of dioxin air pollution.
Community and environmental-movement activism, combined with government regulation, spurred an industry-wide reassessment of waste practices. Clean Air Act (CAA) regulations finalized in 1997 increased the cost, compliance burden, and potential liability associated with onsite incineration. Costs of incinerator equipment maintenance, labor, and energy continued to rise. Healthcare facilitiesimplemented new procedures, sorting nonregulated wastes to prevent needless incineration; new treatment technologies not involving combustion (e.g., autoclave, microwave, chemical and mechanical treatment) came into use in a number of states. The result is that, since 1997, the number of licensed HMIWI units dropped from 2,400 to only 111 (2004).
Problems: Emissions and Energy Use
Incineration remains a legal treatment alternative in most states (check your state rules), but it is associated with serious air-quality concerns. Because atmospheric oxygen is used as the reagent, a large volume of air must constantly pass through the system. Unless the exhaust air passes through a control device, all substances that are volatile at the operating temperature of the system will be emitted with the exhaust stream.
Incinerators are also inherently inefficient from an energy standpoint, particularly when dealing with wastes with high water content. To maintain combustion temperatures, many pounds of fuel must be burned to destroy each pound of waste. Much of that energy is spent simply to boil off the water so that the organic portion of the waste will burn. This has historically been less of a consideration for medical waste, since processing costs are high in any case, but will undoubtedly become more of an issue as the cost of fuel (typically natural gas) increases. Moreover, the burning of large quantities of fuel generates greenhouse gases, primarily carbon dioxide.
Regulatory Considerations
In 1997, the EPA issued Emission Guidelines (EG) to control air emissions for existing HMIWI. The EG apply to most incinerators of hospital waste and/or medical infectious waste, but do not apply when only pathological, low-level radioactive, and/or chemotherapeutic waste is burned.
- Incinerators burning less than 10 percent hospital waste and/or medical/infectious waste by weight (on a calendar quarter basis) are exempt.
- State rules for HMIWI apply, but state regulations are required to be at least as protective as the EG.
- HMIWI are divided into three subcategories based on waste burning capacity (separate emission limits apply to each category):
- medium (>200 to 500 lb/hr)
- Testing, monitoring and inspections must be performed to assure compliance. Records must be maintained.
- HMIWI operators must be trained an qualified.
Pollution Prevention
The following suggestions apply both to facilties with on-site incinerators and to those that send their infectious wastes off-site for incineration.
- Segregate wastes at the source to minimize the volume of actual regulated medical waste (RMW). Further, isolate RMW that must be incinerated; depending on state regulations, at least a small portion of biohazardous waste, including sharps, may have to be incinerated. This will likely include pathological wastes and wastes contaminated with small amounts of chemotherapy substances.
- Minimize the quantity of PVC plastics, products, and packaging (which comprise a portion of plastic wastes in health care) going to incineration. These materials can create dioxins when incinerated. Recycle plastics to the maximum extent possible.
- Do not incinerate mercury wastes, including spill cleanup material.
- Manage CFC-containing wastes separately from incineration wastes.
- Implement alternative technologies for infectious waste treatment, including autoclaving, hydropulping, pyrolysis, microwave, chemical treatment, and irradiation.
More Resources
Call your state or local air pollution control agency.
Hospital/Medical/Infectious Waste Incinerators. EPA website.
New Regulation Controlling Emissions from Hospital/ Medical/Infectious Waste Incinerators. EPA fact sheet (Sept. 1997)
Elimination of Infectious Waste Stream and Improved Operating Efficiencies of the Medical Waste Incinerator, William S.
Middleton Memorial Veteran’s Hospital (case study).
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