Chapter 13: Biohazardous Waste

Biohazardous Waste

Biohazardous waste includes waste materials derived from cultures and stocks of infectious agents, human pathological wastes, contaminated animal carcasses and body parts, all sharps, human blood and body fluids, and chemotherapeutic waste.

Biohazardous Waste Regulations

Proper handling and disposal of biohazardous waste is necessary to prevent infection of personnel (laboratory workers, custodians, laboratory visitors, etc.) and release to the environment. OSHA and Washoe County regulations require that biohazardous waste be properly labeled, stored, and disposed. In some instances, improper disposal of biohazardous waste has resulted in regulatory action and negative media attention. Thus, the handling and disposal of biohazardous waste has important implications with regard to environmental health and safety, regulatory compliance, legal liability, and public opinion.

The Washoe County Health Department (WCHD) is responsible for promulgation and enforcement of local biohazardous waste regulations. Biohazardous waste regulations are available on the WCHD web site (go to “Solid Waste Management”, then Section 080).

The University of Nevada, Reno Biohazardous Waste Operational Plan

The WCHD biohazardous waste regulations require the university to maintain a current operational plan that describes all aspects of biohazardous waste management at University. For full details on biohazardous waste management, consult the University Biohazardous Waste Operational Plan . The following information is a partial summary of the operational plan and is provided as a quick reference for laboratory personnel.

Labeling and Storage of Biohazardous Waste


Waste Containers

At a minimum, all biohazardous waste must be labeled with the universal biohazard symbol (easily visible). Additional information such as the type of waste (such as “sharps”, or “liquid waste”) and origin of the waste is recommended as is appropriate.

Storage Rooms

Rooms or areas used to store biohazardous waste must be labeled with the following warning:


Laboratories where waste is accumulated during experimentation, and where biohazardous waste is not stored, are not considered storage areas and do not have to be labeled as above.


Biohazardous waste must be stored separated from other wastes. Biohazardous waste cannot be stored for more than seven days above a temperature of 0 °C. Waste can be stored up to 30 days if it is kept at or below 0 °C. Sharps can be stored for up to 30 days regardless of the storage temperature. The date that waste is first placed in storage must be clearly marked on the outside of each biohazardous waste storage container or packaging.

These storage timelines apply to any area where biohazardous waste is stored. Storage times do not apply during active accumulation of biohazardous waste; however, waste containers that are full or obviously not being actively used to receive biohazardous waste are considered to be in storage.

Laboratories must decontaminate and dispose of laboratory biohazardous waste on a regular basis to avoid accumulation times that result in unsafe conditions or odor. Matching the biohazardous waste container size to the waste generation rate will avoid an excessively long container fill time and will minimize the need to dispose of partially filled biohazardous waste containers.

Handling and Disposal of Biohazardous Waste


Sharps include all syringes, lancets, scalpels and other similar medical instruments (whether contaminated or not), as well as contaminated Pasteur pipettes, broken glass and other instruments or materials that can cut or puncture personnel.

Sharps must be collected in rigid containers that are leak proof and resistant to puncture from the sharps. Sharps containers must be designed so that sharps can be safely introduced into the container but not easily retrieved (old coffee cans are not acceptable). Containers must be red in color and labeled with the universal biohazard symbol. When the sharps container is approximately 3/4 full, autoclave the container (if possible), secure the lid (tape securely), and submit a request for pickup by EH&S. Approximately once per month sharps are picked by a local waste contractor for treatment and disposal. Sharps containers are available from EH&S by request through the EH&S Waste Management web site.

Contaminated laboratory glassware can be decontaminated by autoclaving or chemical disinfectant and then disposed of as uncontaminated laboratory glassware or broken glass (see below). Small pieces of broken glassware can be disposed of as sharps, or broken glassware can be decontaminated and disposed of as is other contaminated glassware.

Uncontaminated Laboratory Glassware and Broken Glass

Collect uncontaminated laboratory glassware and broken glass in rigid containers (separate from other waste) that will prevent cuts and punctures to personnel. Containers should be labeled “broken glass.” Broken glass is to be disposed of as ordinary trash (to go to sanitary landfill).

Solid Biohazardous Waste

Solid biohazardous waste includes microbial agents, tissue culture, and contaminated material (such as petri dishes, pipettes, gloves, towels, etc.). These materials must be collected in autoclavable biohazard bags that are labeled with the universal biohazard symbol (the bag or the symbol must be red or orange in color). Biohazardous waste must be autoclaved prior to disposal and a visual steam sterilization indicator (such as autoclave strips or tape) must be included on every biohazard bag. After autoclaving, the waste is considered non-infectious and can be disposed of as ordinary trash; however, it is recommended that the autoclaved bag be placed inside an opaque bag prior to disposal. Autoclave bags are available from EH&S and can be requested through the EH&S Waste Management web site.

Solid biohazardous waste generators who do not have an autoclave available for decontamination can coordinate disposal of such waste directly through Waste Management (775-329-8822). Biohazardous waste generated on the main contiguous University campus can be transported to another campus building that has an autoclave suitable for treating the waste; however, autoclaving must be coordinated in advance with the person responsible for the autoclave used (see the University Biohazardous Waste Operations Plan for responsible persons).

Solid biohazardous waste that is stored, or that will be transported to another university building or off-campus location for autoclaving, must be double contained and labeled with the biohazard symbol.

Liquid Biohazardous Waste

Liquid biohazardous waste includes all blood and liquid waste from humans or animals, and all other liquid biohazardous waste (such as microbial cultures). Collect liquid waste in closeable, rigid plastic, leak proof containers labeled with the universal biohazard symbol.

Human and animal blood and body fluids can be disposed of by flushing directly to the sanitary sewer (wear laboratory coat, safety glasses and face shield, and gloves, and be careful to minimize splashing). All other liquid waste must be autoclaved or treated with a 1/10 dilution of commercial bleach (an approximate final concentration of 0.5% sodium hypochlorite) with a minimum of 30 minutes residence time prior to disposal. Treatment of spore-forming pathogenic organisms requires that the 1/10 diluted bleach solution be adjusted to pH 7 prior to treatment. These specific conditions are the only chemical treatments currently allowed for treatment of liquid biohazardous waste.

Animal Carcasses, Body Parts, and Tissue

Treatment and disposal of animal carcasses, body parts, and tissues is coordinated by the Office of Animal Resources (OAR).

Non-infectious carcasses, body parts, and tissues are to be placed in an opaque plastic bag and the bag taped shut with duct tape. Store the bagged materials in a freezer or cold storage area until transport to the OAR facility.

Infectious carcasses are to be collected in an autoclavable plastic bag labeled with the biohazard symbol and taped shut. Secure limbs and sharp protrusions so they will not puncture the bag. Twist the open end of the bag, fold the end over and tape securely. These materials must be stored at -20 °C until transport to the OAR facility.

All animal carcasses are picked up by a local contractor and transported to their facility for incineration.

Human Pathological Waste

Pathological waste includes all recognizable human anatomical remains. Collect human pathological waste in a red, biohazard bag (or other appropriate, labeled container) and place inside a rigid container that can be sealed and which is labeled with the universal biohazard symbol. All human pathological waste will be sent off campus for cremation or interment. Coordinate disposal of human pathological waste through the Curator of the Gross Anatomy Laboratory, Department of Physiology and Cell Biology (775-784-6169).

Autoclaving Biohazardous Waste

Autoclaving is an accepted procedure for decontamination of certain biohazardous waste. Biological cultures and stocks, contaminated solid waste, liquid waste and small animal carcass waste can be sterilized through autoclaving. After sterilization in a steam autoclave, these materials are considered non-infectious. Except for animal carcasses, this bagged waste can then be disposed of as ordinary trash (to go to sanitary landfill); however, it is recommended that autoclave bags containing sterilized waste be placed in an opaque trash bag prior to disposal. Materials that contain hazardous chemicals or radioisotopes are not to be autoclaved (contact EH&S at 775-327-5040 for assistance).

The Washoe County Health Department has promulgated regulations that cover the treatment and disposal of biohazardous waste. Specific University procedures for management of biohazardous waste are contained in the University Biohazardous Waste Operational Plan . The following information summarizes the procedures related to autoclaving biohazardous waste; see the Operational Plan for more detailed information.

To ensure that biohazardous waste is properly decontaminated during autoclaving, Washoe County regulations require that the following procedures be followed.

  1. Treatment of infectious waste must be conducted as specified in the University Biohazardous Waste Operational Plan. For treatment of microbial cultures and contaminated solid waste (e.g., gloves, absorbent pads, and pipette tips) a minimum time of 60 minutes at 121 C (250 F) and 15 psi is required. The total processing time required to decontaminate infectious waste depends on the specific loading factors (container type, water content, quantity, etc.) and in some cases a longer autoclave time may be required.

    Note: Autoclave times of less than 60 minutes must be approved by the IBC. Such proposals must be submitted to the IBC in writing with justification for the shorter time period, and a written SOP that describes the material to be autoclaved, typical waste volume, waste container, autoclave time, and procedure and frequency of autoclave efficacy testing.

    • Sterilization by autoclaving is accomplished through exposure and penetration of the contaminated material by superheated steam for an adequate amount of time. Because steam may not effectively penetrate a sealed plastic autoclave bag, bags containing dry loads must not be tightly sealed (rubber band closures will allow bags to “breath”) or adequate amounts of water must be added to the load. Consult the manufacturer’s instructions for sterilizing materials inside sealed plastic autoclave bags.
  2. All autoclaved waste must include a visual steam sterilization indicator. If the visual indicator fails then biohazardous waste is not considered to be sterilized and must be re-autoclaved.

Autoclave Efficacy Testing

Autoclaves used to treat biohazardous waste must be tested for sterilization efficacy at least once every three months using commercially available Geobacillus stearothermophilus spore ampoules, which contain a suspension of viable spores and are designed for this purpose.

  1. Place ampoule of G. stearothermophilus spores and in the center of an autoclave load (a representative nonbiohazardous waste load can be used as a surrogate).
  2. Process the load under normal operating procedures.
  3. After the autoclave cycle is completed retrieve the spore ampoule and incubate it with a nonautoclaved control ampoule at the recommended growth temperature (as prescribed by the spore ampoule manufacturer’s directions).
  4. After completion of the incubation period, inspect the ampoules for growth as described in the manufacturer’s instructions. Lack of growth in the test ampoule indicates that the autoclave conditions were sufficient to inactivate the heat resistant spores, and thus provides good assurance that the autoclave conditions are sufficient to kill more heat sensitive microbial agents.
  5. If an autoclave fails an efficacy test, any waste that was autoclaved during the failed test is not considered to be sterilized and must be re-autoclaved. The failed autoclave cannot be used to treat biohazardous waste until efficacy testing demonstrates adequate autoclave conditions are achieved.

In addition to quarterly efficacy testing requirements, the performance of autoclaves used to treat biohazardous waste must be verified through efficacy testing at the following times:

  1. Prior to initial use to treat biohazardous waste (whether unit is new, reconditioned, or pre-existing)
  2. Upon relocation of pre-existing, previously tested autoclaves
  3. After maintenance, repair, or calibration that has potential to negatively affect autoclave performance

Autoclave Records

The following records must be maintained for each autoclave used to treat biohazardous waste for a minimum of three years:

  1. Each autoclave cycle used to treat biohazardous waste, to include:
    1. date and operator name
    2. autoclave temperature and pressure
    3. general description of waste load, including waste containers (e.g., 2 small bags of solid waste)
    4. quantity of biohazardous waste* (record number of containers by type or volume of liquid waste)
    5. autoclave run time
    6. results of visual indicators (e.g., heat sensitive tape) used to verify adequate autoclave conditions
    * Quantity of solid waste in pounds is estimated during end or year reporting by assigning nominal weights to container types or converting liquid volume to mass.
  2. All autoclave maintenance, calibration, and repair
  3. All autoclave efficacy tests and results

Contact the BSO for a template of an example autoclave log sheet that includes fields for all required information.

Chapter 14: CDC/USDA Select Agents