41.   But the gas is also problematic.

42.   But the gas is always hot and is usually mixed with sulfur and other smelly compounds.

43.   But these gases are normally in balance, and our unnatural contribution to them has thrown that balance off.

44.   But when he got to the front of the line at a station on his way out of town, he found there was no gas left.

45.   By all accounts the gas is a bargain.

46.   Carbon monoxide detectors are more and more common in homes, but the odorless, colorless gas can also be a problem on the road.

47.   Carrying extra gasoline in that manner is illegal in many places because gas is so volatile that sparks can ignite its fumes.

48.   Coal was a cheaper fuel for generating electricity, but gas was cleaner, and the plants were cheaper and easier to get built.

49.   Critics of the assault have complained that the gas was a potent chemical that could have harmful effects, especially on children, and should not have been employed.