Marijuana is becoming a big business and many are hoping this will eventually drive out the illegal pot farmers and their environmental reckless pest control tactics. However, not everyone is so sure. Legal pot could just create a larger market for the drug, which in turn could make it more lucrative to grow the crop illegally. On this episode of Bloomberg Environment's podcast Parts Per Billion, we speak with reporter Sara Merken about the environmental hazards of growing marijuana and about the future of this crop as it slowly moves out of the shadows.