Autoclave (Steam) Treatment of Infectious Medical Waste

Infectious Medical Waste & Disease Control

Autoclave (Steam) Treatment of Infectious Medical Waste

The use of an autoclave for the treatment of Infectious Medical Waste is addressed in Section 10 of the West Virginia Infectious Medical Waste Rule, 64CSR56.

The following information is only relevant to infectious medical waste wastes that are autoclaved and intended to be disposed in a sanitary landfill.


Operational Parameters

An autoclave is a hollow metal vessel that combines steam (high temperature) and high pressure for a set period of time in order to inactivate microorganisms.

In West Virginia, autoclaves used to treat infectious medical waste must be operated at or above approved temperature, pressure, and time settings. The Infectious Medical Waste Rule lists the following settings as acceptable:

Temperature (F) Pressure (P.S.I.) Time (Minutes)
250 15 90
250 80 28
270 32 30
270 80 16
272 27 45

Other settings may be approved by the Infectious Medical Waste Program. However, before other settings are approved, documentation must be provided that indicates that the unit can achieve a reliable kill at design capacity at the altered settings. This documentation must be submitted along with a written request for the operational variance.


Procedures for Use and Record-Keeping

When an autoclave is used to treat infectious medical waste, each load of waste must have a piece of temperature-sensitive tape attached.

At the end of the cycle, if the tape has not changed color the cycle must be considered unacceptable and treated again.  Please note: If the second cycle fails to produce a color change on a new piece of tape, the autoclave should be examined for problems.

All infectious medical waste treated in an autoclave must be documented in a log book.

  • The log must contain the following information for each load treated:
    • Date, time, and autoclave operator
    • Type and amount (pre-treatment weight) of waste
    • Post-treatment result from the temperature-sensitive tape
    • Dates and results of calibration
    • Dates and results of spore testing


Spore Testing Requirements

  1. Autoclaves must be evaluated for effectiveness at a minimum of every forty (40) hours of operation. 
  2. The WV Infectious Medical Waste Rule requires the use of Bacillus stearothermophilus spores for this testing because of their high heat resistance. Facilities may use any type of instant read test strips or any other bacterial spores for daily checks, but they must also spore test every forty (40) hours of operation using Bacillus stearothermophilus.
  3. The results of all tests must be recorded in the autoclave log book.


Additional Requirements

  • All infectious medical waste that is to be treated in an autoclave must be collected at the point of generation, in biohazard-labeled bags that are orange in color.
  • The disposal of treated infectious medical waste in a sanitary landfill must comply with the WV Infectious Medical Waste Rule, as well as WV Department of Environmental Protection and US Environmental Protection Agency regulations.
  • The Infectious Medical Waste Rule states "that treated, noninfectious medical wastes that are shredded so that they pass through a 1/2" screen are no longer considered recognizable".
    • These wastes does not require any labeling when sent to the landfill.
  • For treated wastes that are not shredded, the West Virginia Infectious Medical Waste Rule requires a label to be affixed to each container before being sent to a landfill.
    • It is the policy of the West Virginia Infectious Medical Waste Program to allow the use of a waste manifest in place of labeling each waste container.
    • Labels must at least 3" x 5" in size and must be securely attached to the outer layer of packaging. It may also be a tag that is affixed to the packaging. Indelible ink must be used to complete the following information for labels and/or manifests:
      • Name, address, telephone and fax numbers of facility
      • Weight of the treated noninfectious medical waste
      • The type of treatment process that was used to render the waste noninfectious
      • A signed and dated certification which states:
        "I hereby certify under penalty of law that this waste has been rendered noninfectious in accordance with procedures required by the West Virginia Infectious Medical Waste Rule, 64 CSR 56."