Witnesses said two men ran from a motel room on the 12100 block of 14th Street immediately after the explosion, ripping off their shirts as if they had been burned, and drove off.
Officials initially thought a meth lab exploded, but now they say someone was trying to extract THC from marijuana plants, which is a highly volatile process.
Authorities said one suspect was taken to a hospital for burn injuries. The other is still on the run.
