11.   But other studies have found gulf war veterans do have higher rates of chronic illnesses, which might be related to low-level exposure to chemical agents.

12.   But joining those elements for the main line failed to produce the spark expected from the signature collection, as if two chemical agents were neutralizing each other.

13.   But rumors persist that South Africa may have used chemical agents against Mozambique a decade ago.

14.   But the detection devices all showed negative readings for chemical agents in the air, the officers said.

15.   Caught by surprise, the government countered that the Soviets apparently were deliberately mixing in pollen with their chemical agents, in order to enhance their poisonous effect.

16.   Chemical agents are not so easy to keep safely in stable condition, and their dispersal depends largely on climatic factors.

17.   Chemical agents were released at least three times in the last six years on Johnston Island.

18.   Chen has applied for a patent on a companion device that will shoot a chemical agent into the soil, deactivating the land mines.

19.   Danciu later filed a Freedom of Information Act request and received documents showing the U.S. military used the island to test lethal chemical agents during World War II.

20.   Cragin said there have already been attempts to use chemical agents in the United States.