One by-product of America's massive health care and medical research industry is approximately 500,000 tons of contaminated refuse, equipment and biological materials.
Because the infectious, hazardous and toxic agents in the waste could contaminate our environment, its proper disposal presents unique problems.
Currently, the country disposes of most of this waste in approximately 2,400 medical waste incinerators (MWI) located in hospitals, clinics and laboratories. This disposal method has consistently been effective in disinfecting contaminated waste, destroying hazardous organic compounds and reducing waste volumes. On-site incineration also is a convenient way to manage wastes and to control disposal costs.
However, the future of medical waste disposal practices - and the role of incineration as the primary disposal technique - could change significantly depending upon the outcome of pending MWI air emissions rules proposed by the U.S. Environmental Protection Agency (EPA).
MWIs can be potential sources of various air pollutants. Depending upon the waste type, the incinerator type and the operating conditions, certain pollutants may be emitted. These include particulate matter (PM), opacity, CO, chlorinated di- benzo dioxins and dibenzo furans (CDD/CDF), HCl, SO2, NOx, Pb, Cd and Hg. In general, however, most U.S. MWIs are small and have limited emissions potential.
Still, the Clean Air Act (CAA) requires EPA to establish incinerator emission standards, including those for medical, hospital and infectious wastes. These standards, referred to as MACT, or "maximum achievable control technology," must maximize reduction of air emissions, while taking into account the costs, energy requirements and any health and environmental impacts.
In February 1995, EPA published proposed new source performance standards (NSPS) and emission guidelines (EG) for MWIs. The deadline for the final rule has been slated for mid-April 1996.
The proposed rule's substantial new requirements for MWIs include:
* environmental and social impact assessments for siting new MWIs;
* operator training and qualification;
* annual compliance testing;
* continuous monitoring of emissions and operating parameters;
* emission limits for numerous pollutants (see table); and
* comprehensive recordkeeping and reporting.
Emission limits for new MWIs were based on the best performing MWI reviewed. Limits for existing MWIs were based on the best performing 12 percent of units in each subcategory. Using specified levels of current emissions is called the "MACT floor." The evaluated MWI subcategories were continuous, intermittent and batch processing incinerators.
The proposed emission limits will affect most, if not all, types and sizes of new and existing MWIs, and will likely require using dry sorbent/activated carbon injection systems or an equivalent. Due to retrofit costs, as many as 80 percent of existing facilities may be forced to close.
A Sweeping Review Organizations such as the American Hospital Association and several MWI equipment vendors quickly reacted to the rules, which resulted in a sweeping review of the proposed emission limits.
At the heart of the issue is the need to reassess the MACT floor for different categories of new and existing MWIs. When the proposed rule was prepared, EPA only had data from eight emissions tests at seven MWIs. To compensate for the insufficient background information, EPA developed emission standards using available data from existing air quality permits and from state regulations.
However, EPA did not have an up-to-date inventory of working MWI types and locations; this information would be necessary as a base for setting the MACT floor. Consequently, to estimate the quantity of MWIs in states with only partial or no inventory data, the agency could only use data from states where information was available. Thus, EPA estimated that 338 continuous, 3,018 intermittent and 336 batch MWIs exist nationwide.
Parties who commented on the proposed rules found this method to be flawed, noting that significantly fewer than 3,700 MWIs operate in the United States. In addition, they said, EPA's estimated number of MWIs was particularly high for states with the most stringent MWI air regulations,.
Thus, EPA was faced with a dilemma: lowering its estimates of MWIs that currently meet stringent regs would potentially increase the emissions allowed by the MACT floor. Fortunately, the agency's reevaluation only moderately increased the PM MACT floor. As a result, in some cases "good combustion practices" may now be adequate for compliance.
Meanwhile, EPA is considering tailoring emission limits according to MWI type. For example, small batch or intermittent units may be required only to maintain good combustion practices instead of having to add expensive control equipment. EPA also reportedly is reconsidering its requirements for expensive continuous emissions monitors and annual stack tests.
Such changes are not guaranteed, however, and EPA still may take a conservative approach. In fact, it's possible that the final rule's key requirements will remain relatively unchanged from those initially proposed.
Impacts On Disposal In the grand scheme, the rule could accelerate existing trends in medical waste management or could create new trends. For example, if many small MWIs become economically infeasible to operate, the demand for contract disposal services may increase.
To meet this demand, regional MWI facilities may crop up around the country. These facilities' costs, however, could skyrocket due to the NSPS technical requirements and having to deal with the vigorous public opposition that these facilities inevitably elicit. The final result will likely be an increase in disposal costs for many waste generators.
Another avenue would be alternative treatment technologies, which currently claim a small share of the medical waste disposal market. These technologies generally shred the waste before or after it's been sanitized with a chemical disinfectant or with steam. Several reputable vendors for alternative systems exist, and many facilities have had good experiences with them. Potential drawbacks include performance problems, air emissions, failure to destroy hazardous wastes and possible exposure of operators and maintenance personnel to untreated waste.
Future Prospects No matter what form the new rules take, they will almost certainly spur generators to reuse, recycle, segregate waste and source-reduce. For example, facilities contracting disposal services may find that reusing medical equipment will help to keep costs down. And facilities with on-site MWIs may divert items such as mercury batteries and x-ray film from the waste stream in order to meet emission limits without installing additional emissions controls.
It's still uncertain how many existing MWIs will be economically able to continue operating under the new rule. Substantial changes in medical waste disposal practices may be necessary.
At press time, the prospects appear bleak for EPA to complete the reevaluation and to finalize changes in time for this month's deadline.
For now, facility owners should prepare to react to the rules whenever they are finalized and avoid retrofitting for the unknown. Rather, they should perform an internal audit of medical waste flow and analyze their current medical waste treatment and disposal costs. Finally, planners as well as the decision makers must stay abreast of the issues.