Characteristics and storage of hazardous healthcare waste

Many healthcare facilities produce hazardous waste. The mostly widely accepted definition of hazardous waste (at least in the US), is RCRA hazardous waste - that is, waste that meets the criteria laid out in the Resource Conservation and Recovery Act (RCRA) of 1976 and the Hazardous and Solid Waste Amendments to RCRA of 1984. State and local governments can have their own definitions and regulate waste in their own ways, but when you say “hazardous waste” to a waste management professional, he or she thinks RCRA waste.

This page talks about what makes healthcare waste hazardous. If the waste is also infectious, that is another issue. Sometimes healthcare waste is both hazardous and infectious, or hazardous and radioactive, and must be managed to meet the requirements for more than one type of waste.

Some medical waste meets the definition of RCRA waste. There are four lists of enumerated hazards (F, K, P and U) and medicines appear on two of the lists (P and U). Further, some waste streams are highly (1) corrosive, (2) reactive, (3) ignitable, and (4) toxic, either with or without the characteristics that make them medical waste. For instance, blood soaked up by rag soaked in flammable solvents could be both medical and hazardous waste. Some chemotherapy drugs are included on the P and U lists and other chemotherapy drugs developed after the lists were written still qualify for RCRA hazardous status because of their toxicity.

The most salient feature of hazardous wastes is not whether the waste is a solid or a liquid, or its heating value or density - those are important engineering parameters to be accounted for in designing treatment and storage - but the nature of the hazard and potential to harm people and facilities.

Ignitable medical waste

Flammability or inflammability (they are the same thing) does not make a waste hazardous or necessarily of special concern. Many wastes will burn (that’s why incineration is an appealing treatment). Indeed, most waste generated in the typical office, or even industrial setting, will burn. But burnable or flammable is not the same as ignitable. RCRA says that ignitable waste is hazardous. That is, the waste must be liable to being set on fire with a spark. The metric used to quantify ignitability is the flashpoint.

The flashpoint of a liquid is the temperature at which a vapor above the waste ignites when exposed to a spark. The lower the flashpoint, the more flammable the material. If a waste has a flashpoint below 140 °F (60 °C), it is hazardous. Powders and other solids may be ignitable, too. Paints and cleaning solvents often become ignitable waste. Anesthesia gases and ethylene oxide are hazardous materials used at many hospitals. If a waste meets the Department of Transportation’s definition of oxidizer, it is considered ignitable waste. Solid waste is classified as ignitable if it can spontaneously catch fire or ignite through friction. The EPA has a process for measuring ignitability.

Corrosive medical waste

Highly acidic or alkaline liquids are considered corrosive. Aqueous wastes with a pH below 2 or above 12.5 are classified as hazardous. If the liquid is demonstrated as being corrosive to steel coupons in a controlled test, it is also classified as corrosive and assigned RCRA waste code D002. Corrosive materials at health care facilities include acids (e.g. acetic, chromic, hydrochloric, nitric, sulfuric) and bases (ammonium hydroxide, potassium hydroxide, sodium hydroxide). Physically solid, nonaqueous wastes are not considered corrosive under RCRA.

The EPA spells out a standard test to measure if a waste is corrosive on steel.

Reactive medical waste

Reactive refers to chemical reactivity and the potential of a material to rapidly breakdown or react in a manner that releases a lot of heat or gases and vapors. It is difficult to quantify how reactive something is and whether it passes a threshold to become hazardous. It’s mostly a judgment that comes out of a conversation with the regulatory authority. A waste that is liable to chemical breakdown spontaneously at ambient temperatures is considered reactive. So is anything that reacts with water. If toxic fumes or gases (including sulfide or cyanide gases) form, the material is considered reactive. Context matters, too, as two materials present in the same facility that might react with each other could be considered reactive waste while each material by itself might not. Reactive materials at health care facilities include oxidizers (bleach, hydrogen peroxide, potassium dichromate, potassium permanganate) and reducers (sodium bisulfite, sodium sulfite).

Toxic hazardous waste from medical facilities

A waste is toxic if it is harmful to a human (or similar animals) after it enters the body. Toxicity here is a chemical property. Bacteria and other pathogens can be harmful, but they are not considered toxic. Heavy metal waste is often toxic. Used batteries often have heavy metals. Some facilities (often older ones) have lead built into the walls and ceiling of areas where X-rays and CT scans are done. Medical treatment chemicals can be toxic. Some chemotherapy drugs are genotoxic. Wastes on the P-list are usually toxic, but the The test used to tell if a waste is toxic is the toxicity characteristic leaching procedure.

Do I have to measure these characteristics for every batch of waste we produce?

No. The regulatory agencies could force you to test every batch, but as a practical matter your operating permit will allow you to test the waste stream periodically. If your waste characteristics are stable over time, you shouldn’t have to measure the toxicity, flashpoint, and pH all that often. If in doubt, apply the precautionary principle and regard waste you might suspect might be hazardous as actually hazardous.

Medical facilities employ materials that produce hazardous waste but which are not unique to the healthcare industry. These might be found at any large facility with diverse activities: herbicides, paints, pesticides, and waste oils.


You have to get a hazardous waste permit if you treat hazardous waste or if you store it on site. Every facility’s permit is different. You will have to monitor, test, and file reports about the waste you generate and store. This might sound daunting but the administrative burden of applying for and maintaining a permit depends on how complex your operations are. Large quantities of waste and diversity of waste means a more complex permit. The EPA requires that any facility that generates over 100 kg/month of hazardous waste get an EPA Identification Number and submit regular reports to the agency. Your state agency may have similar requirements.

Decades ago hazardous waste permits were more onerous but as society and the regulatory agencies have become more comfortable with them, they are not as scary as they once were. Getting a permit will help protect you in case of lawsuits so they provide something of an insurance policy.

The EPA has four categories of generators:

  • Conditionally Exempt Small Quantity Generators (CESQG) - sometimes refered to as Very Small Quantity Generators (VSQG) - generate no more than 100 kg of hazardous waste (as defined by RCRA) per month
  • Small Quantity Generators (VSQG) - generate 100 kilograms and 1000 kilograms per month. Cannot have over 6000 kg of waste on site.
  • Large Quantity Generators (LQG) - generate more than 1000 kilograms of hazardous waste per month. Must ship waste off-site within 90 days of generation.

Heavy Metals

Waste management pros worry about metals specifically named in RCRA. The so-called RCRA 8 metals are not allowed in MSW at high concentrations. Above the stipulated limits, the waste becomes hazardous RCRA waste.

The limits are:

Arsenic 5 ppm (mg/l), D004
Barium 100 ppm (mg/l), D005
Cadmium 1 ppm (mg/l), D006
Chromium 5 ppm (mg/l), D007
Lead 5 ppm (mg/l), D008
Mercury 0.2 ppm (mg/l), D009
Selenium 5 ppm (mg/l), D010
Silver 5 ppm (mg/l), D011

Don’t think you can get out of this requirement by diluting your waste so the concentration is lower. If authorities figure that out, they will punish you.

Large generators, small generators, etc.

The EPA has published a useful guide:

Materials and tools used to clean up a spill of hazardous waste must be treated as hazardous waste. When you register your facility with the EPA as a hazardous waste generator (and you should), you will get an identification number. This number should be printed on the outside of every container of RCRA waste shipped off site and included on the shipping manifest.

In the United States the federal government regulates hazardous waste and facilities that generate waste on a regular basis are classified by size of waste stream

chemotherapy warning Large Quantity Generators (LQGs) = facilities that generate more than 1,000 kg of hazardous waste per month

Small Quantity Generators (SQGs) = facilities that generate between 100 kg (approximately 220 lbs) and 1,000 kg of hazardous waste per

Conditionally Exempt Small Quantity Generators (CESQGs) = facilities that generate less than 100 kg of hazardous waste per month

Most US hospitals are CESQGs or SQGs.

Hazardous waste storage

Hazardous waste should be stored in a dedicated area. This should be under a roof - and preferably inside a building with four walls. It doesn’t have to be air conditioned but it should have a sprinkler/fire suppression system. It should not be in an area where people frequent. If hazardous waste must be stored in an area that is used for other activities, be sure to have plenty of personnel protection equipment (e.g. eye washes) nearby. If you have a federal permit to keep hazardous waste on site, you must inspect the containers at least once a week. We recommend inspection of all waste containers once a week whether you have a permit or not and even if the waste is benign. The EPA requires hazardous waste inspection logs include the date and time of observance, the name of the person doing the inspection, and any abnormalities or risks observed. Corrective actions recommended and performed should also be noted.

What constitutes an inspection? Use your best judgement. A checklist that the inspector goes through during his or her tour will be useful and shows diligence. The “inspector” here should be a responsible person who knows what the storage should look like and who can see leaks. A record of the completed checklist, either in paper form or electronic, should be filed, as proof that the facility is taking storage of hazardous waste seriously.

Generating facilities need to get an EPA Identification (EPA ID) number using EPA Form 8700-12. You will need this number when submitting reports and for putting on shipment manifests and markings.

As a condition of your permit, the EPA requires you report every two years how much waste you made and what you are doing to reduce it.

Transport to Disposal

Healthcare facilities almost always have a waste management contractor that takes away hazardous waste for treatment and disposal.

For hazardous waste shipments, the EPA distinguishes between bulk and non-bulk containers. Bulk containers are larger than 119 gallons (450 liters) in volume and 882 lbs (400 kg) in weight. The EPA calls the external sign on bulk containers “placards” and the one on non-bulk containers “labels”. Labels have this specific definition and they must be diamond shaped. Additional information on the containers is called “markings”. Non-bulk containers must include an external marking that says: “HAZARDOUS WASTE: Federal Law Prohibits Improper Disposal. If found, contact the nearest police or public safety authority or the U.S. Environmental Protection Agency.” Each shipment must also have an EPA tracking number.

The healthcare facility must write up a manifest for every shipment that leaves the facility. If there is a treatment facility that receives the waste, it will sign off and you - the generator - should get a copy so you know the waste has been responsibly transferred. Further, when the waste goes to preparation for disposal, the generator again gets notice. The EPA allows electronic manifests (e-manifests) to be employed.

If you do not get notice that your waste shipment has gone to final disposal, you should follow up and pester those responsible. You are always responsible for that waste, so you want to make sure it gets to disposal.

If you ship hazardous waste off-site, you still need to submit a report to the EPA every two years. The report states how much hazardous waste you produced, where it went, and how you are planning to reduce the quantity and severity of waste in the future.

Universal Waste

Universal waste is a category that is larger than RCRA hazardous waste. It includes RCRA hazardous waste, but also other waste items that are dangerous or pose risks to the environment but which are not covered under RCRA.

Different states can have different definitions. Batteries, computer equipment, light bulbs, televisions, aerosol cans, and pharmaceutical waste (that does not meet RCRA criteria) can all be included. It is up to each state to determine what counts as universal waste, but the federal EPA has something to say about storage of universal waste where it is generated.

Small quantity handlers of universal waste (SQHUW) are those that have less than 5000 kg on site. They are allowed to keep the waste on site for up to a year and they do not need an EPA Identification Number. Employees should be trained in handling of waste and as to its hazards.

Large quantity handlers of universal waste (LQHUW) are those that have less than 5000 kg on site. These facilities do need an EPA Identification Number.

The EPA also has requirements for universal waste transporters and universal waste destination facilities. See the EPA page: