When equipment is used to clean up a job site with hazardous waste and debris contaminated with toxic material, decontaminating the equipment after it is used is not only important to the health and safety of upcoming operators, but to the mechanics, drivers and the people who may come into contact with it in the future.
A company involved in remediation job sites that contain hazardous materials should have a policies and procedures manual to guide field personnel through the equipment decontamination process.
Briefly, the process for equipment decontamination is as follows:
- Map the area where the equipment decontamination will occur, identifying topography, access routes to the area, evacuation routes, areas of the site where personal protective equipment is required, monitoring stations, run-off retention ponds, and storage tank area.
- Set up the decontamination area away from and preferably upwind from areas of remediation, construction and site operation activities.
- Establish work zones: exclusion zone (the contaminated area), which also includes a pre-decontamination area; contamination reduction zone (CRZ), where decontamination takes place; and support zone, an uncontaminated area where workers should not be exposed to hazardous conditions.
- Personnel stationed in the CRZ are the site safety officer, decontamination station operator, and emergency response personnel.
- The CRZ includes the decontamination area, a worker rest area that has toilets, sitting area, liquids and shade, wash facility with potable water, and a drainage area for water and liquids used during decontamination.
There are several methods for constructing a decontamination area. Companies rent and sell specialized and portable decontamination stations for heavy equipment with raised wash pads, heavy solids troughs, walls, ramps, water recycling systems and pressure washers.
Or, contractors can build their own cleaning stations using impermeable rubberized sheeting, buffers around the outside to contain the run-off water, curtains, drains, water containment areas, pumps and storage tanks for the hazardous water. If possible, the pad should be constructed on a level, paved surface and should facilitate the removal of waste water. This may be accomplished by either constructing the pad with one corner lower than the rest, or by creating a sump or pit in one corner or along one side. A sump or pit should also be lined.
When cleaning the equipment, workers must wear safety goggles, gloves, rubber boots and, depending on the type of hazardous material, biohazard suits and masks to prevent exposure to the hazardous substance.
Tools and solutions used for decontamination include:
- Long-handled brushes, rods, and shovels for dislodging contaminants and contaminated soil caught in tires and the undersides of vehicles and equipment.
- Pressurized sprayers for washing and rinsing, particularly hard-to-reach areas.
- Rinse solutions selected to remove contaminants and contaminated wash solutions.
- Curtains, enclosures, or spray booths to contain splashes from pressurized sprays.
- Containers to hold contaminants and contaminated soil removed from tires and the undersides of vehicles and equipment.
- Wash and rinse buckets for use in the decontamination of operator areas inside vehicles and equipment.
- Brooms and brushes for cleaning operator areas inside vehicles and equipment.
Water should be periodically removed or drained from the decontamination pad.
At the completion of site activities, the decontamination pad should be deactivated and properly disposed of. The pit or sump should be back-filled with the appropriate material designated by the site project leader, but only after all waste/rinse water has been pumped into containers for disposal.
Equipment decontamination can be as hazardous as working in a contaminated area. Precautions must be taken to protect workers and the environment from contamination both inside and outside the job site.