There were fearsome enough weapons before World War II, including poison gas and germ warfare.

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Iraq's former president is on trial for the deaths of 180, 000 people, many killed by poison gas.

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"The symptoms she displayed - unconsciousness, vomiting, pinpoint pupils - they all correspond to poison gas exposure, " he says.

BBC: Middle East

With the Chemical Weapons Convention (CWC) awaiting action by the U.S. Senate, the treaty's supporters are asserting that the Tokyo subway poison gas attack demonstrates the need for U.S. ratification.

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Another might be fear that the aliens would retaliate with even more devastating weapons, in the same way that no one used poison gas in World War II for fear of the consequences.

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At a seminar in Abu Dhabi this week, Major-General Patrick Cordingley, a Briton who commanded a brigade in the Gulf war, maintained that Gulf security was still threatened by potentially hostile neighbours (read Iraq and Iran), ballistic missiles, lethal agents like poison gas, and internal unrest.

ECONOMIST: The Gulf

Additionally, the day guard arrives early each morning to check for any gas or poison that might be leaked inside the classrooms.

CNN: STORY HIGHLIGHTS