Clinical Laboratory Waste
Clinical laboratories generate three primary types of waste: chemical waste, infectious (biohazard) waste, and pathological (large tissue) waste. This section contains information on correct disposal as well as environmental best practice for managing laboratory wastes.
Numerous chemicals used in laboratories must be managed for disposal, and most of the time this means in the RCRA hazardous waste stream. Laboratory waste from analyzers, calibrators, cleaners, reagents, stains, and test kits must be evaluated to determine whether they are hazardous.
Chemical constituents, contaminants, and preservatives found in laboratory chemicals may be considered hazardous at very low levels. Product inserts may fail to disclose information about small amounts of preservatives and contaminants, even though the product may still be considered hazardous under RCRA or MN01 lethality laws. Due to the vast number of chemicals used in a clinical laboratory, you will likely need to have an expert evaluate your laboratory wastes to ensure you are in compliance with disposal; your hazardous waste disposal company should be able to provide this service to you.
When solutions are rinsed off slides or equipment and discharged to the sewer, this is considered disposal. The solutions must be evaluated before they are diluted by the rinsing process, and generators who intend to discharge waste to a sanitary sewer must notify their publicly owned treatment works (POTW), also known as wastewater treatment plant, before discharge. A common alternative is to use a staining rack placed over a tray so that you can easily collect the used stain for hazardous waste disposal.
Examples of chemical waste in a clinical laboratory may include:
- Fixatives such as B-5 and Zenker’s are hazardous waste for the toxicity characteristic (mercury)
- Clinitest tablets (both unused AND used) are reactive, corrosive, and MN01 lethal
- Parrafin/xylene is ignitable and listed as D001 and F003 and must be treated as hazardous waste
- Wright’s stain is ignitable and listed as D001 and F003 and must be treated as hazardous waste
- Ictotest tablets (both unused AND used) are corrosive and must be treated as hazardous waste
- Hemocue Hgb cuvettes are reactive and must be treated as hazardous waste
- Reagents such as “Solution A” are toxic and must be treated as hazardous waste
For more details on how to properly dispose of RCRA (chemical) waste, please visit the healthcare hazardous waste section of our website
Infectious (red bag) waste
Biohazard infectious waste is commonly called “red bag waste” in healthcare. The red bag waste stream is appropriate for (1) blood waste, (2) laboratory waste, and (3) regulated human body fluids. The primary treatment for this waste is by autoclaving (sterilization) at a licensed disposal facility. Oftentimes this waste is then compacted and sent to a special landfill.
Common red bag wastes in a laboratory setting include:
- Fluid blood or bulk body fluids
- Human derived Albumin
- Live or attenuated vaccines that are infectious to humans
- Laboratory wastes (such as cultures, biological agents, and associated lab items) that are infectious to humans
For more details on how to properly dispose of infectious waste, please visit the healthcare infectious waste section of our website.
Pathological and large tissue (yellow bag) waste
Pathological and large tissue wastes are biohazard wastes that require incineration rather than sterilization as a final treatment. Most of the time, this waste is designated by the use of yellow bags and will be managed by the same disposal company as your red bag waste. Yellow bag waste is appropriate for (1) pathological waste, meaning human tissues and body parts removed accidentally or during surgery or autopsy intended for disposal, and (2) Research animal waste, meaning carcasses, body parts, and blood derived from animals knowingly and intentionally exposed to agents that are infectious to humans.
Common yellow bag wastes in laboratories include:
- Human tissues from pathology and histology labs
- Carcasses from research animal waste
Some laboratories do not generate pathological waste; however, whenever your lab is dealing with human or animal tissues you must ensure you are using yellow bags rather than red bags.
For more details on how to properly dispose of pathological waste, please visit the healthcare infectious waste section of our website.
Environmental best practice for managing laboratory waste
- Recycle your formalin, ethyl alcohol, and xylene. These chemicals are very easy to recycle, distill, or filter, which can save you money and prevent many gallons of waste from entering the waste stream. MnTAP has developed a Formalin recycling fact sheet with information on these processes.
- Manage all chemical wastes as hazardous. When solutions are rinsed off slides or equipment and discharged to the sewer, this is considered disposal. Laboratories who intend to discharge non-hazardous laboratory waste to a sanitary sewer must first notify their POTW before discharge. Even if the final product does not contain toxic levels of chemicals, it is rare (if not impossible) to find entirely “green” laboratory chemicals on the market. Therefore, best management would be to collect these solutions and chemicals and treat them as healthcare hazardous waste. This ensures that you are keeping as many chemicals out of waterways as possible.
- Avoid purchasing chemicals in bulk. When you end up with outdated laboratory chemicals, most require disposal in the RCRA hazardous waste stream. To prevent this waste, you should evaluate the ordering process for these chemicals. “Buy in bulk” discounts are no help if a product expires. If you find that you have more on the shelf than you can use before expiration, try calling others in your healthcare facility network to share your product before it goes bad, or try listing it on the Minnesota Materials Exchange if it is not yet open.
- Reduce the number of “red bag” containers in your laboratory. It is common to want to put red bag containers in several places around the facility. After all, in healthcare, don’t they belong everywhere? The answer to this is generally no. Regular patient rooms, exam rooms, nursing stations, and the like typically do not need their own red bag waste stream containers. Focus your efforts on places likely to generate the bulk of this waste, and remember to keep things such as exam gloves and paper towels out of this waste stream. An evaluation of your waste by your infectious waste disposal company may afford many opportunities to reduce the amount of red bag waste you generate in your laboratory and thus the costs associated with this waste stream.
- Reduce the size of the bags (and containers) you use. Filling containers until full is less wasteful than tying off large red bags that are only partway full. If you aren’t producing enough waste in one area to fill a bag each day, consider switching to a smaller container with a smaller bag to save money on bags and reduce plastic waste. If you are using a 55-gallon bag in a small procedure room, you could probably downsize. Furthermore, smaller bags have the advantage of being removed more frequently, reducing odor issues.
- Whenever possible, avoid the use of reagents containing arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver. Though it can sometimes be difficult to find “good” substitutions in laboratory settings, they can and do exist. Spending a little time researching what types of “less toxic” chemicals other laboratories are using can be a great way to lessen the overall environmental footprint of your laboratory.