A gas explosion in a Barcelona apartment building Monday left an elderly man dead and his infant granddaughter with slight burns, officials said.

The Interior Ministry in Madrid said the blast was caused by a tank of butane gas, which is often used in Spanish homes for cooking and heating. The ministry said it had no other details.

The Barcelona town hall said, however, that firefighters believed the blast may have been caused by a camping stove in an apartment occupied by an 80-year-old man, his wife and their 5-month-old granddaughter.

The blast started a fire, and the man died of a heart attack, a town hall official said on condition of anonymity because department rules bar her from disclosing her name.

The building is still standing, and the blast did not weaken its structure, the town hall official said.