1.   An apparent propane leak triggered explosions at a gas-processing plant, propelling fireballs and smoke into the sky.

2.   Officials suspected a gas leak triggered the blast on Thursday.

3.   Officials suspected a gas leak triggered the explosion.

4.   Officials suspected a liquefied petroleum gas leak triggered the explosion, which buried motorists in cars, toppled utility poles and smashed windows and storefronts for blocks around.

5.   Officials suspected a liquified petroleum gas leak triggered the blast, which buried motorists in cars, toppled utility poles and smashed windows and storefronts for blocks around.

6.   Toledo said a gas leak apparently triggered the blast at the Humberto Vidal shoe store in Rio Piedras, a residential and shopping district in San Juan.

7.   Toledo said a natural gas leak apparently triggered the blast at the Humberto Vidal shoe store in Rio Piedras, a residential and shopping district in San Juan.

8.   Toledo said a gas leak likely triggered the blast.

9.   A gas pipeline leak triggered a huge blaze in the remote far north of Russia Thursday but authorities said there were no casualties and the situation was under control.