Anthrax Decontamination Procedure for Buildings and Structures

Environmental Project Designer James Thomsen has developed a procedure for decontaminating buildings and structures where anthrax is found. The procedure was developed for the Hart Congressional Building, but according to Thomsen, can be used for any contaminated structure. It will be made available at problem addressed by the procedure is to remove all risk of anthrax exposure to building occupants and eliminate secondary or cross contamination exposure risks to a building, structure, or operation contaminated with anthrax. It is based on a building purge and disinfections procedrure developed in 1995 for the Albany NY School System for a one-million square foot, high school building contaminated with bacteria, mold, fungi, and othe rindoor air contaminates. What follows is an overview of the process in which Thomsen identifies the procedures involved with decontamination, as well as logistical provisions.

Anthrax Decontamination Procedure for Buildings and Structures
By James M. Thomsen, Environmental Project Designer
Original Design by Failsafe Risk Management Alternatives
Copyright 2001 All Rights Reserved ISI

Developed for the Hart Congressional Building

Problem: To remove all risk of anthrax exposure to building occupants and eliminate secondary or cross contamination exposure risks to a building, structure, or operation contaminated with anthrax.

Concept: Based on a building purge and disinfections procedure developed in 1995 for the Albany NY School System for a one-million square-foot, multi-level high school building contaminated with bacterial, mold, fungi and other indoor air contaminates: The decontamination process used was based on asbestos and radioactive pcb environmental cleanup protocols. Similar protocols can be used to remove all mobile anthrax contamination and then kill residual anthrax in place with a final encapsulation of all air handling ducts with antibacterial encapsulation.

Cost: The one million square-foot building, including total design, project oversight and equipment, materials and labor was under $50,000.00.

Time needed: One week. 24/7 Shifts. Pinnacle Environmental, Guilderland NY

Staff needed: 60 Abatement technicians, 12 project managers, 6 testing and documentation consultants.

Equipment needed: 100 to 200 Negative Air HEPA Filtration units used for asbestos abatement with 2000 cfm or greater capacity. Six roof top multiunit HEPA filtration units; 24 HEPA High Capacity 99.99% efficacy UV light treated, 20 backpack HEPA , 24 Leaf blowers, 9 carpet steam cleaning agitator heads to attach to HEPA vac with vibrate and brush carpet and contamination into the HEPA Vacuums. 9 Truck Mounted Steam Cleaning Machines for carpet. 20 Sub micron misters. 12 airless paint spraying units. Poly Hangers, EPDM Roofing Membrane, Reinforced fire resistant 6 mill poly, 10 Fibrous Aerosol Monitors, 24 High volume air sampling pumps, 8 PM Ten Air sampling Systems, Six long arm portable 1000 lumen lighting devices, four laser generators, 30 UV light Illumination Systems, and standard asbestos abatement supplies and personal protective equipment. Garden pump sprayers, decon rags, disinfections solutions, spray glue, ABC binding compound by Fiberlock Technologies. Electrical and water support

Process: Identify hot, warm and cold contamination zones. Seal off with two level poly walls systems with outside being made positive pressure and inside negative pressure of minus 3 inches of water with controlled push pull equalization. Seal all windows, doors and openings as per standard asbestos abatement regulations.

Create zones: Remove rooftop or mail ventilation supply ducts and attach 10,000 CFM reverse airflow in system pulling into HEPA filter capture. Starting with the outside perimeter, collect all papers, personal effects by room and photograph locations and box and seal in poly to outside decontamination using irradiation or warehouse UV light treatment and hand disinfections as designed. Then establish complete control over zone by zone ventilation makeup and exhaust both HEPA filtered with negative air machines changing the air 100 times per hour with fume hood velocity at makeup air points. Begin leaf blowing all surfaces carpet and fixtures towards the ventilation ducts which now have high powered reverse HEPA filtration suction flow pulling contamination up into the ducts into the roof top or large units tapped into the mail supply and exhaust HVAC Systems. This creates a large fume hood velocity inside the building all being HEPA captures. All HEPA filtered machines are exhaust ducted into 55-gallon drums of bleach solution using a bubbler to catch any blow-by of anthrax particles. Leaf blow and agitate all surfaces until inside Fibrous Aerosol monitors show no particulate left in the airflow. Then use carpet cleaning agitation units on dry HEPA vacs and agitate and scrub all carpets with agitation in three directions. After FAM shows clear air, leaf blow all surfaces again toward air collection ducts or negative air machines. Install freestanding negative air machines as air washing machines with the containments and begin treatment of carpets with hospital disinfectant of all carpet and solid surfaces with infection solution using sub micron foggers. All surfaces are then wiped dry. Steam clean carpets for final carpet clean and then install high intensity UV lights to dry and treat each zone for final disinfections step. Upon completion of clear FAM results and clear air high volume and microvacuming results with clear swipe samples and tape samples, place EPDM rubber roofing membrane on the floors and spray encapsulation with airless sprayer on all poly walls and barriers to encapsulate the ducts using airless sprayers and misters. Then with the encapsulation drawn up and out through the ducts into the rooftop or large negative air units the contamination in the ducts and HEPA filters are sealed.

Leave poly walls in place and seal ducts and openings to maintain protection from other adjacent areas undergoing cleaning. pray above ceilings and crawl spaces with encapsulation and then positive pressure the space after all sampling shows clearance to outside air background levels

Hot Zone carpet and fixtures are removed and replaced with new materials. All aspects are monitored by close circuit television systems and two project managers are with each zone crew. Standard asbestos abatement decon system established with captured water using disinfections solution. Later, the carpet will receive a scotch guard treatment as a final step after the area is cleared

Contact, James M. Thomsen Sr. 917-309-5698, for specific details, floor plans, and project management flow-charts.

ISI, 79 Fillmore Ave. Tonawanda, NY, 14150, 716-694-6390, email:, or visit

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