1.   An explosion, believed to have been caused by grain dust, made a shambles of the huge storage complex.

2.   But its experts publicly have attributed the explosion to the presence of volatile grain dust in an underground conveyor-belt tunnel.

3.   Explosions in grain elevators are caused by the mixing of grain dust and oxygen in closed quarters.

4.   Flammable, airborne grain dust is strongly suspected as the cause of the explosion, although no agency has made that a formal finding yet.

5.   Grain dust, Bergman said, is an unavoidable problem throughout the industry.

6.   Grain dust, ignited by a spark, caused a flash fire.

7.   In both cases, OSHA investigators cited missing or faulty equipment meant to guard against unsafe conditions that can trigger explosions in the highly combustible grain dust.

8.   Investigator Vernon Grose told The Wichita Eagle newspaper last summer that a seized bearing in that machinery caused friction and generated enough heat to ignite grain dust.

9.   Joe Black, a grain merchandiser for the company, said Monday night that he had no knowledge of complaints against the company concerning excessive grain dust.

10.   Q. Why is grain dust in elevators explosive?