Question: When the birds attack the town a gas station attendant is hit by a bird and drops the gas hose he is using to fill a car. The gasoline flows down the street and under a car; a man drops a match and lights the gas causing an explosion. Why didn't the gas pump shut off when the man dropped it?
Answer: The movie takes place in the 1960s, so presumably gas pumps worked a bit differently back then. This is also a small town and probably the gas station had not modernized. There may not have been automatic shut-offs, or if there was, it was faulty.
The automatic shut off is in the handle of the hose. When a person grips the handle they have to lift a levered switch to allow gas flow; the lever is spring loaded so that if it is released the gas will stop flowing. I have looked at older antique gas pumps and they are all the same; even the visible glass gravity flow ones. If that hose was dropped the the gas should have stopped flowing.
Answer: Arthur was voiced by three actors. Rickie Sorenson and Richard and Robert Reitherman. Rickie originally voiced Arthur but, during production of the film, Rickie hit puberty causing his voice to change, so Wolfgang Reitherman chose to use his own sons to replace Rickie.