1.   On Wednesday, opponents of the plant released an engineering study showing that the incinerator was emitting toxic chemicals into the atmosphere.

2.   Scientists at the University of New South Wales in Australia have found that certain kinds of seaweed emit chemicals called furanones that interfere with bacterial communication.

3.   The ozone-creating chemicals are emitted from vehicle tailpipes, as well as industry smokestacks and a variety of other sources.

4.   They emit a chemical that apparently makes them band together and march in single file.

5.   And different algae and weeds that have replaced the familiar green algae emit a chemical that makes drinking water taste foul.