Is your staff wise in waste management?

Medical Laboratory Observer,  April, 1991  by Gerald A. Hoeltge

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Is your staff wise in waste management?

All laboratorians must learn their labs' protocols for hazardous waste disposal, including emergency plans and comprehensive procedures for storage, packing, and hauling.

As anyone who has worked in a clinical laboratory for a long time knows, the amount of hazardous material waste that we generate is growing constantly. Chemical analyses, tissue fixation, and staining procedures each produce their share of chemical wastes. An inevitable byproduct of microbiologic testing is infectious waste. When we introduced the concept of universal precautions, we began to treat nearly all clinical wastes as infectious. The increasing use of disposables has exacerbated the issue of waste management.

While the total amount of waste is increasing, our greatest concern is for the portion that is hazardous. We must identify any refuse that could injure an employee or damage the environment--and learn to handle it properly. At the Cleveland Clinic Foundation, about 80 pounds of hazardous chemical waste are generated per 1,000 square feet of laboratory space each year--and the lab occupies well over 100,000 square feet. Within the same space, we generate about 1 ton of infectious waste and about 10 tons of general refuse annually.

As managers, we must insure the correct disposition of all laboratory wastes. Some materials, such as spent solvents and photographic developers, can be reclaimed. Chemical treatment of selected wastes may reduce their hazard level. Managers who understand local sanitary sewerage codes may direct employees to flush a variety of solutions down the drain. On-site incineration may be acceptable for other types of waste. In all but the smallest laboratories, the logistics of disposing of certain materials requires signing a contract with a vendor of waste management services.

Employees need to know the disposal strategy that management has chosen for each category of waste. They should be able to select the right containment system, understand how to label or otherwise identify the packaging, and know where it should be placed for safe disposal. The potential for spills, fires, floods, and other emergencies mandates contingency planning.

Such issues are best addressed in a formal training program. We recommend that waste handling be addressed at the time of new-employee orientation, whenever waste-generation realities or disposal protocols change, and annually thereafter.

* Identifying hazardous wastes. Chemical wastes may be identified by their characteristics. A corrosive is a substance that can cause visible destruction of human tissue at the site of contact: strong acids (pH<2.1) and highly alkaline liquids (pH>12.5). Ignitable liquids include those that have a low flashpoint or are strong oxidizers. Few clinical laboratory wastes are truly reactive--that is, capable of explosive detonation or able to emit dangerous vapors when mixed with water. The term toxic refers to any substances that can cause serious biologic effects when small amounts are inhaled, ingested, or absorbed. Regulatory definitions are provided in Title 40 of the Code of Federal Regulations, Part 261.

Infectious wastes include discarded microbiologic cultures; human blood and body fluids, as well as materials contaminated with such fluids; and human tissues. An operational definition for medical wastes includes discarded sharps and infectious wastes. (New York, New Jersey, Connecticut, Rhode Island, and Puerto Rico are regulated under the Medical Waste Tracking Act of 1988.) Although Federal regulations do not establish which materials must be handled as medical wastes in most parts of the country, some state and local regulations spell this out more explicitly. Consult all applicable codes before establishing your laboratory's medical waste policy.

* Packaging and storage. Waste solvents, such as xylenes and alcohols, often assume the greatest share of a laboratory's hazardous chemical wastes. Such solvents should be stored with the same fire protection considerations as are afforded to their reagent sources. Details are available in the Flammable and Combustible Liquids Code, National Fire Protection Association (NFPA) #30. The storage problem may be more severe for hazardous wastes if they are allowed to accumulate before transfer and disposal.

There are two basic methods for preparing hazardous chemical wastes for transport. In the first, wastes are poured into individual containers labeled with the name and concentration of the chemical and the date. Labeled containers are packed in steel drums, each of which must house compatible chemicals. The bottles must be surrounded by enough absorbent material to contain the contents even if all the primary containers were to fail. The drum must be properly labeled concerning its contents.

Outside vendors tend to prefer to do the packing of barrels they will transport. Because such materials can be stored on site no longer than 120 days, the packing must be done at least three times per year.