TRACY (CBS13) – Two men and a woman were critically injured in an explosion and fire as they were attempting to convert marijuana into butane honey oil at an apartment in Tracy on Friday night, according to police.

An explosion occurred at about 9 p.m. inside a residence at the Paradise Apartments at 1441 Parker Avenue. Multiple fire companies and medical units were required at the scene.

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All of the surrounding apartments were evacuated and the fire was contained and extinguished in the one unit. No one else was injured.

All three were taken to the UC Davis Burn Unit with extensive burns covering up to 90 percent of their bodies.

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Because of the nature of the explosion, members of the San Joaquin County Metro Narcotic Task Force, the California Department of Justice and the California Office of Emergency Services were called to assist in the clean-up and investigation.

Butane honey oil or hashish is extracted from marijuana during an extremely dangerous process that utilizes butane and heat. Improper ventilation and the presence of an open flame or spark can result in an explosion.

A criminal case for manufacturing of a controlled substance may be forwarded to the San Joaquin County District Attorney’s Office pending completion of an investigation after interviewing the two men and woman, who weren’t able to be sufficiently questioned because of their injuries, police said.

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Police said they aren’t releasing the names of the individuals yet because no arrests have been made and all family members hadn’t been notified of their injuries.