The Environmental Protection Agency is in charge of regulating pesticides and other chemicals used on agricultural products. But it turns out there's one crop that they don't care if it's poisoned: Marijuana.

Since it is illegal at the federal level, the EPA does not regulate the use of pesticides and other chemicals on marijuana plants. In June, a prominent pesticide manufacturer even tried to get some of their products approved by the agency, but they were rejected. Not only is the legality of marijuana a problem, but the EPA's also lost much of its power and authority under President Trump as deregulation has become a major theme for the administration. Therefore it is left up to the states themselves to test and regulate those chemicals.

Unfortunately, many states either have lackluster or no regulation whatsoever of marijuana pesticides. For instance, California has allowed medicinal marijuana for over 20 years but will only begin testing for pesticides in 2018. One cannabis testing lab in California found that three to four out of every 10 samples they receive tests positive for a pesticide not approved for use on marijuana. 

Some states have dramatically improved their testing procedures to make their products safer. In 2016, nearly half of all cannabis tested in Colorado came back positive for unapproved pesticides. After the state changed regulations, that number is down to only 13 percent this year. 

One of the most common pesticides used to grow marijuana is myclobutanil, which is particularly problematic because it's known to release a poisonous gas when heated. Obviously, that is a problem when it comes to marijuana. Myclobutanil use prompted a recall of many marijuana products in Canada earlier this year. 

Many of these pesticides, such as myclobutanil, are not even necessary in growing marijuana. But the lack of standards and regulations leaves growers to their own devices, which can lead to ill-informed decisions. States will need to ramp up their own regulatory actions and investigations to ensure cannabis being sold in their state is up to par.