Driving through the streets of The Toy district in downtown Los Angeles, LAPD Detective Keith Honore points out the blocks of former toy shops, which are now occupied by smoke shops.
"They're popping up everywhere," he said. "It's just like going to the store and purchasing a candy bar."
LAPD narcotics detectives are focused on the legal product, fueling an illegal drugmaking empire.
"We've seen people pick up 10-15 cases. That's a lot of fuel."
Butane is used to convert marijuana to an even stronger form — known as honey oil — or BHO. For the last year, NBC4 has been tracking the rapid rise.
The detectives who investigate BHO labs are part of Los Angeles' Interagency Metropolitan Police Apprehension Crime Taskforce — known as L.A. Impact. In 2013, they busted 11 butane honey oil labs. Last year, they busted five times as many, according to detectives.
L.A. Impact gave NBC4 unprecedented access to its investigations.
At a raid in Downey, two brothers were accused of running a small, but sophisticated operation.
"They've been at for awhile," Honore said.
But even more alarming was the imminent threat to their own family.
"We could have been dealing with a child fatality," the detective said.
Two young girls were living just feet from potential disaster. Nearly a third of all BHO labs in LA County are only discovered when they explode.
"It's so dangerous to put that much butane in one area," Honore said. "It's just so volatile."
All it takes is one can and a heat source to blow up a room, detectives said. Labs are often found with thousands of butane cans.
In a raid in Diamond Bar, investigators seized a quarter of a million dollars worth of honey oil and 7,000 butane cans.
"Before this BHO phase, we did not see this amount of butane being sold," Honore said.
It's easy to buy. A recent transaction took five minutes and $145. It yielded 96 cans of butane and an extraction tube. There is nothing illegal about the sale, but detectives want to see butane purchases monitored like cough medicine and spray paint, both household items criminals use for illegal activity.
"If you go to Home Depot or Lowes and you try to buy a can of paint it's locked isn't it?" Honore said. "You have to show ID. There are no locks, no cages, no anything down here."
Detectives fear that unless butane sales are regulated, the BHO epidemic will continue to grow.
"If we had the manpower, we would probably be working 24 hours a day," Honore said. "We'd never go home."