TEWKSBURY, Mass. (AP) — Authorities say an explosion at a Tewksbury home that sent two men and a woman to Boston hospitals with serious burns appears to be drug related.

Fire Chief Michael Hazel says the explosion that blew out windows at about 9:15 p.m. Tuesday may have been caused by a buildup of vapors from butane used in a marijuana THC extraction process.

He said Wednesday the process was performed near an electric stove and the vapors came into contact with an ignition source.

Full and empty butane cylinders were found at the scene.

Police are looking for two people who may have fled the home just before the explosion.

Chief Timothy Sheehan tells The Sun (http://bit.ly/P09vxD ) the victims had burns to their head, hands and face. No names were released.

Hazel estimated damage at $200,000.