As marijuana becomes a viable industry in the United States, monitoring the safety of its crop has gradually become an industry in itself.

Washington state and Connecticut, two of the twenty states and Washington, D.C. that permit marijuana use, require weed to pass laboratory examination before it's distributed to the general public, for either medicinal or recreational means, the Seattle Times reported. (Recreational weed is legal in Washington and Colorado only). Common contaminants found in marijuana such as mold, mildew, e. coli, and insect parts mean more states will likely add stricter testing policies in the future, according to the Times.

Though contaminants are commonly found on marijuana, their effects aren't well known and have never been the primary cause of death. In a study conducted from 1997 to 2005, however, weed was the secondary cause of death in 279 cases (not just from contamination but all types of cases), according to the Times. A study from this year also found that pesticide-infused weed posed a "significant toxicological threat."

Current testing is in place to ensure that compromised weed doesn't become a future problem.

"Although we have not seen significant problems with tainted marijuana in the past, we should certainly be taking steps to make sure it's not a problem in the future," said Mason Tvert, a spokesman for the Marijuana Policy Project in Washington, D.C. "We have never seen a death solely associated with marijuana use. The same certainly can't be said of alcohol and other drugs."

At a University of New Haven lab in Connecticut, the focus is on developing a simpler, more reliable test specific to weed. Current techniques are the same ones used for testing other plants and have been around for several decades, according to the Times.

"What we're trying to do is put the information together in a user-friendly format," said Heather Miller Coyle, a forensic botanist and associate professor at New Haven. "Having some better technology in place is a good thing."

"If there's no certification ... it's like saying we don't check our meat for mad-cow disease," Coyle said. "That's our goal as a private university, to develop the tools to address or mediate this issue."

Coyle's lab also aids the area's law enforcement. She can differentiate between naturally-grown weed and sythetically produced strains using THC and determine the geographical source of illegally-grown marijuana, the Times reported.