Candy Smith is thankful that she wasn't yet home from work Thursday afternoon when an explosion tore through her townhouse building in Douglasville.

"Thank God I was not here, or my children," she told the AJC on Friday.

Smith said her children, ages 13, 6, 5 and 2, would normally be riding their bikes near where the explosion occurred at the "Laura's Manor" complex on Dorsett Street.

A maintenance worker at the complex suffered severe burns in the explosion and subsequent fire.

The cause of the explosion is not known, but residents reported a natural gas odor before the incident.

The townhome where the explosion occurred was vacant, fire officials said.

The structure partially collapsed, and 12 units were evacuated.

The burned maintenance man was transported to Grady Memorial Hospital in serious condition.

His name has not been released, but Smith called him a "good guy" who was fortunate to survive the blast.

Smith said she's been praying for the man and his family.

"It's very bad that he's been hurt from this," Smith said. "How bad the explosion was, he could have been wiped out instantly."

Atlanta Gas Light investigators will do several tests to try to determine what happened, a company spokeswoman said. It could take several days to uncover the cause of the explosion, she said.

The AJC's George Mathis contributed to this article.