COLTON (CBSLA.com) — A homeowner purging his gas line while smoking a cigarette caused his home to explode and go up in flames, fire officials said.

The blast happened about 6:30 p.m. Thursday in the 800 block of North Rancho Avenue in the Inland Empire city.

The man is hospitalized with third-degree burns all over his body. He was able to speak when authorities arrived. His dog was killed in the explosion.

Firefighters are not sure why the man was purging the lines and say it’s always something you should have the gas company perform.

The explosion is under investigation.