Videos of explosions at various BHO production facilities keep surfacing online - and the images of Breaking Bad-style labs threatening to blow up the neighborhood are setting back the public perception of cannabis as a legitimate medicine.

But making concentrates isn't a sure-fire recipe for disaster, provided it's done properly. In the case of one recent explosion at New MexiCann Natural Medicine, The Albuquerque Journal reported that, after an investigation, the federal Occupational Safety and Health Administration found a total of 12 serious health and safety violations.

How do BHO labs work?

In order to understand why these labs keep blowing up, one first needs to understand what BHO, or butane hash oil, is. As the name suggests, it involves taking large amounts of ground marijuana, putting it in a cylindrical glass or stainless-steel canister, and pushing a solvent (usually butane) through it. The process strips the cannabis of its cannabinoid-rich oils, producing a mixture that's then purified and cooked into a solid, like shatter.

"One common method of butane removal," according to Wired, "includes boiling it off in a hot water bath, while another involves the use of a vacuum pump and vacuum chamber to lower butane's boiling point, pulling butane from the oil. The resulting, super-potent concentrate can then be vaporized or consumed as dabs.

It seems that most of the worst BHO explosions have taken place in facilities that weren't properly ventilated, where the equipment was moved around often, potentially damaging and causing leaks in the butane lines, or - worst of all - in the kitchens and garages of amateur extract-makers who don't know what they're doing.

Why it's so explosive

"Butane hash oil production can be explosive even when one takes appropriate safety precautions," writes Oscar Pascual of SF Gate, "but some oil blasters increase the risk by attempting to speed the process with heat. Once the butane seeps through the pot and spits resiny goo into a container, the solvent will naturally boil off at room temperature (30 degrees Fahrenheit, technically). But the goo must be worked a little to pop all the tiny bubbles of residual butane, and heat quickens the pace. So some stoners turn their kitchen burner to low and put the butane-rich slurry on top—which is like simmering a pot of gasoline—only to be reminded that fuel plus oxygen plus ignition source equals ka-boom."

In short: buy concentrates only from reputable dispensaries whose methods aren't putting their employees and neighbors at risk. And above all: don't try this at home.

And, here's how bad it could be: watch the accident at that New Mexico dispensary: