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Europe’s politicians had their eyes stung by tear gas at the EU summit in
Nice last week, as air conditioning units sucked the gas—which was fired
by police at rioters—into the meeting centre. But Honeywell of New Jersey
has developed a way to keep riot gas and chemical and biological warfare agents
out of buildings. The firm notes that terrorists using an asthma inhaler to
spray the nerve gas sarin, say, into an aircon intake could kill a large number
of people. To tackle the problem, the company has developed inflatable balloons
that sit in the corners of the aircon ducts (WO 00/58658). The balloons contain
a substance that can be triggered to expand rapidly as soon as a gas detector
sniffs a risk. The bladders block the ducts, keeping any dangerous gases out of
the building.