Cleaning and Disinfection of Anthrax-Contaminated Sites and Materials

This page is part of the Guidance Document Repository (GDR).

Looking for related documents?
Search for related documents in the Guidance Document Repository

Note: Current research indicates that the use of lime (e.g. whitewash or other calcium products) is contraindicated for use as a disinfectant for anthrax-contaminated sites. Therefore, where possible, avoid using these products as a disinfectant for anthrax sites, carcasses, or materials. Provincial legislation, however, may supersede this recommendation.

Wear personal protective equipment (PPE) when dealing with cleaning and disinfection (C&D) products. Read the label of these products for personal protection information.

If using sprayers for disinfecting sites and materials outside, be aware of wind direction when spraying to avoid unnecessary exposure to disinfectants.

1. Treating Contaminated Soil

If possible, remove soil at the site of an anthrax carcass to a depth of 20 cm, and incinerate or heat treat. Because this method is not practical in most situations, disinfect with 12.5% formalin solution (5% formaldehyde) at 50 litres/square meter.

Note: C&D is not required if an animal died at pasture and the carcass was disposed of on-site without being moved.

2. Cleaning Equipment

  • Be aware that formaldehyde/formalin solutions that are diluted to 10% have the ability to inactivate anthrax spores. According to label directions, a 37% solution of formalin can be diluted one part formalin to nine parts water to obtain a 10% solution.
  • Remove organic material and soil from any equipment to be disinfected.
  • Use hot water and a detergent to wash organic material, such as hair and blood, from equipment. Wash water should be directed into the burial or burn site. Once organic material is removed from equipment, spray formaldehyde onto the surface with a contact time of at least 30 minutes.
  • Leave disposable materials (boot covers, latex gloves) on-site, and burn or bury with the carcass; otherwise, materials can be disposed of via biohazardous waste disposal sites or by incineration.

Other disinfectants with activity against anthrax spores include chlorine – a 6% household bleach solution diluted at a one part bleach to two parts water; and peracetic acid at a 3% solution.

Autoclaving, if available, is also an effective means for sterilizing equipment.

3. Treatment of Structures

When an animal dies within a structure, disinfection of contaminated surfaces requires the following three-step approach.

a) Preliminary disinfection

  • Use either 30% formalin (10% formaldehyde) or 4% glutaraldehyde (pH 8.0–8.5).
  • Apply 1–1.5 litres/square meter.
  • Apply all disinfectants for an exposure time of at least 2 hours.
  • If using a high pressure cleaner, use caution to prevent spreading contamination – pressure should not exceed 1.5 litres/min (10 bar).
  • Disinfect contaminated equipment (e.g. shovels, trucks, post-mortem knives, protective clothing, etc.) by soaking or saturating with 10% formalin solution.
  • Any contaminated materials too difficult to clean and disinfect (e.g. straw, manure, etc.) may be disposed of with the carcass.

b) Cleaning

  • Clean all surfaces by washing and scrubbing with hot water. Continue until original colour and surfaces are restored and waste water is free of dirt particles.
  • Remove residual water.
  • Leave surfaces to dry.
  • Avoid high pressure cleaners, as they could potentially spread contamination through aerosols. If used, the water pressure should be adjusted to deliver 13–15 litres/min (80–100 bar).

c) Final Disinfection

  • If blood is present, use
    • either 30% formalin (10% formaldehyde) or 4% glutaraldehyde (pH 8.0–8.5); or
    • 3% hydrogen peroxide or 1% peracetic acid.
  • When using glutaraldehyde, hydrogen peroxide or peracetic acid, treat the surface twice with an interval of 1 hour between applications.
  • Avoid using formaldehyde and glutaraldehyde at temperatures below 10°C.
  • Apply all disinfectants at a rate of 0.4 litres/square meter.
  • Apply all disinfectants for an exposure time of at least 2 hours.

Caution: Avoid skin contact or inhalation when using disinfectants. Follow label handling instructions.

4. Treating Clothing, Boots, Tools

  • Remove visible organic material and soil on clothing and boots at the burn or burial site.
  • Wash footwear with water and detergent; a disinfectant may be applied.
  • Be aware that rubber boots are easily cleaned and disinfected. Leather footwear should not be worn when disposing of carcasses.
  • Know that standard clothes-washing procedures will remove any residual spores that may have adhered to clothing. Wash clothes separately from other household laundry.
  • Spray equipment with 10% formalin, and soak overnight.

For more information on C&D disinfectant products, please refer to the Compendium of Veterinary Products.

Date modified: