RESTORx of Washington provides Tear Gas Cleanup Services for all of Western WA. We have seen a recent 'wave' of Police Actions where a person or persons have holed up in a building. The Police attempt to negotiated with the people involved until the threat to Public Safety necessitates forcible removal of the people from the premises. The Police's initial and primary tool to incapacitate, (in order to allow capture and removal), is Tear Gas.
Tear Gas is introduced to the building area in question by high powered mortars / guns. The Tear Gas canister is fired through windows into the occupied areas. The force of the projectile is sufficient to penetrate triple pane windows and then penetrate walls into wall cavities. We have seen situations where over 100 canisters have been used on a single property.
Once the Tear Gas has been introduced into the area in question, most but not all tear gas canisters will explode. The tear gas explosion releases a substance that quickly turns into a white or reddish dusty residue. This tear gas residue will settle on all surfaces. Depending on the amount of canisters fired, tera gas residue can accumulate from 1/8 inch on up.
Tear gas cleanup of this residue is very labor intensive. It is not uncommon to clean the entire structure 5 to 6 times before the contamination is eradicated. It is also not uncommon for some canisters to penetrate wall cavities and not explode until the movement caused by drywall demolition activates the canister, creating a recontamination. Any agitation in tear gas cleanup can cause existing tear gas residue to activate, making cleanup very difficult for workers in the space, even with full Personal Protective Equipment. It is important to remember that Tear Gas fired in the streets will dissipate quickly, whereas Tear Gas fired into a confined space will not.
Should Tear Gas be introduced to your building, we recommend the following initial steps be taken as quickly as possible:
1. Contain any doorway exit of the affected area with 4-6 mill plastic. The odds are that at least one doorway will be damaged by the Police, so 2 or more layers may be required.
2. Do not let people, (workers), enter and leave the tear gas affected areas, as the contamination is easily spread, and there will most likely be broken glass and blood throughout the area.
3. If affected areas are served by HVAC, you should shut it down immediately. (Any HVAC units servicing the area should be shut down at the beginning of Police Activity.)
4. When multiple tear gas canisters have been fired into a unit that has a common hallway, expect secondary tear gas contamination in the hallway and adjoining spaces. If an elevator is in the immediate area, shut it down.
Tear gas cleanup is not a cleaning job to try to do on your own. All personnel involved in the cleanup should be trained in Bio-Hazard and Chemical Cleanup.
Tear Gas is typically composed of two chemicals:
1) AlphaChloroacetophenone known as CN, and
2) Orthochlorobenzylidenemalonitrile known as CS.
These chemicals are powders that are dispersed as an aerosol. After approx. 30 minutes the tear gas chemicals in the aerosol settle on surfaces. The tear gas chemicals are no longer in the air, but the CN and CS residue is still on the surfaces. These chemicals can cause characteristic tear gas symptoms that include a sharp burning sensation of the skin and mucous membranes, involuntary closure of the eyes, profuse tearing and a runny nose.
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