The explosion that heavily damaged a Tewksbury residence Tuesday night was the result of an illegal lab where someone was using butane to extract THC from marijuana, according to the Tewksbury Fire Department.
“This was a very dangerous situation for the residents and the firefighters,’’ Tewksbury Fire Chief Michael Hazel said in a statement.
Hazel said that “the buildup of butane vapors within the apartment came in contact with an ignition source and an explosion ensued. The process was being performed on and around an electric stove within the apartment.’’
THC, the acronym for tetrahydrocannabinol, is the active constituent of marijuana.
The explosion injured two men and a woman and caused an estimated $200,000 in damage to the four-unit residence at 22 Astle St., according to the department. The three injured people were taken by medical helicopter to Boston hospitals. Their conditions were not immediately available.
A second alarm was struck, and mutual aid firefighters responded to the scene from Billerica, while units from Wilmington and Andover also responded for coverage, fire officials said.
A number of full and empty and butane cylinders were found at the scene, Hazel said.
The incident is under investigation by the Tewksbury fire and police departments, state troopers assigned to the office of State Fire Marshal Stephen D. Coan, and the State Police bomb squad.