The use of powerful and dangerous pesticides on illegal cannabis farms has only grown in past years.

A joint operation between federal and California state authorities has sought to crack down on illegal marijuana grow-ops in the Golden State. The move came out of fear around potentially dangerous pesticides that have been detected in illicit cannabis products. And the samples evaluated from this year's raids show a startling trend - use of these dangerous chemicals are on the rise.

90 per cent of the raided farms had been using pesticides credited with poisoning wildlife, and which have the potential to threaten water supplies. That's up from 75 percent last year, and rates six times as high as what was seen in 2012. And as Mourad Gabriel, a researcher specializing in the ecological impact of illicit grow sites says, just a quarter teaspoon of these chemicals is enough to kill a 300-pound bear.

Over the course of the crackdown, 95 farms were raided and over 10 tons of fertilizers, pesticides and other chemicals were removed. Officials are stressing that the ecological impacts of these illicit grow sites is the real concern and the primary reason for their persecution.

"This isn't about the marijuana, it's about the damage that’s being done," U.S. Attorney McGregor Scott said in an interview before a news conference to announce the findings. "What is happening here is illegal under anybody's law."

As the cannabis industry continues to grow alongside mounting global environmental crises, scrutiny of weed's ecological footprint will only increase.