1.   Most commonly, gasoline was dripping from pipe connections beneath pumps.

2.   Phil Wurthier, left, checks the pipe connections from a portable water drill rig to a mud pit at a water development training school in Cleveland, Texas.

3.   The use of malleable iron products, which include pipe connections, is widespread in the construction and auto industries.

4.   They are more likely to be poorly installed, contain outdated technology or have corroded pipe connections.

5.   He said a small amount of hydrogen escaped through a faulty pipe connection before the leak was discovered Sunday.