Paper contaminated with tear gas

Judith Murphy <jamurphy<-a t->unm< . >edu> writes

>I received a request about decontaminating some family papers that
>were heavily (49 cans) exposed to a tear gas substance called "CS"
>that formed a powder that is still active and irritating after
>several weeks.

CS is the designation for (o-Chlorobenzylidene)malononitrile, which
as she mentions is commonly called a tear gassing agent. It's
poisonous by ingestion, intraperitoneal, and intravenous routes and
is considered moderately toxic by inhalation. Chemical data suggests
that has relatively low systemic toxicity, but as those who have
been gassed know, it is an *intense* irritant of the eyes, skin and
mucous membranes. It has been described as feeling as though one's
eyes and skin are on fire.

It's a white power which vaporizes when released. CN tear gas
vaporizes better than CS, so CN is usually used indoors. CS forms
more of a dense cloud, so it is often used outdoors--such as in riot
control.

The powder on the documents may be (probably is?) the CS agent.

CS tear gas is still being used by a variety of police departments.
In fact, Ms. Murphy may want to begin by obtaining an MSDS for the
product. It might be easiest to go to a company still selling the
product, such as Galls 800-477-7766) and ask to be faxed the MSDS.

In terms of respiratory protection the minimal level would be a
full face-piece respirator with organic vapor canisters and high
efficiency particulate filters (although please keep in mind all of
the OSHA requirements for medical supervision and fit testing when
respirators are used). Also, chin style canister respirators are
recommended for this chemical. I would also recommend gloves and
perhaps even Tyvek suits to keep the powder off your clothes.

CS is relatively insoluble in water, but is soluble in acetone and
benzene (neither of which you probably want to use). One approach
might be to aggressive air the documents under warm forced air. This
may help to vaporize the remainder of the CS. Obviously the
ventilation would need to be fed outside (not back into the
building!).

Hope this helps.

Michael Trinkley, Ph.D.
Director
Chicora Foundation, Inc.
PO Box 8664
Columbia, SC  29202-8664
803-787-6910

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                 Conservation DistList Instance 10:108
                   Distributed: Monday, June 9, 1997
                       Message Id: cdl-10-108-009
                                  ***