In this June 21, 2018, photo, Dave Egerton, vice president of technical operations, demonstrates how he uses an instrument capable of analyzing small organic molecules to look for pesticides in cannabis samples, at CW Analytical Laboratories, in Oakland, Calif. California's new rules require testing of marijuana for pesticides and contaminants such as heavy metals, solvents and mold. They also say edibles must be tested to determine concentrations of the mind-altering ingredient THC. (AP Photo/Jeff Chiu)
