31.   Thousands of compounds exist naturally, adding to synthetic ones that release chemicals into the air.

32.   Although there was some damage, no chemicals were released and there were no casualties, she said.

33.   Environmental groups said the crude extraction methods released poisonous chemicals into the air and nearby streams and wells.

34.   EPA scientist Michael Hodanish said burning tires, batteries and furniture can release dangerous chemicals such as lead, sulfuric acid and vinyl chloride into the air.

35.   He did not know how much chemical was released.

36.   No toxic chemicals were released, Omdahl said.

37.   Psychiatrist Dr Deva Dass explains that nerves in the brain communicate with each other by releasing chemicals called neurotransmitters from their nerve endings.

38.   That process may have released chemicals that produce sulfur and the greenhouse gas carbon dioxide.

39.   The new theory is that these were vaporized by the asteroid impact, a process that would have released chemicals that produce sulfur and the greenhouse gas carbon dioxide.

40.   The so-called Antabuse pellets release a chemical which, when mixed with alcohol, makes the patient sick.