31.   Its underground tank exploded when inspectors on a routine check for leaks failed to fully secure a valve, state gas officials said after a preliminary investigation.

32.   Problems storing LPG are under review, with underground tanks being the favoured solution.

33.   The bill was amended to give gas stations with just one underground tank five years to comply with the law.

34.   The U.S. military also constructed five-to-seven large surface oil tanks, an unknown number of underground tanks and a deep-water port.

35.   The waste fluid was stored in the underground tanks.

36.   The plant consisted of three overground tanks and one huge underground tank.