"Even after legalization, illicit cannabis grows continue to pollute California’s public lands. And the contamination, new research shows, lingers."

"Law enforcement raided the illegal cannabis operation in Shasta-Trinity National Forest months before, but rotting potatoes still sat on the growers’ makeshift kitchen worktop, waiting to be cooked. 

Ecologist Greta Wengert stared down the pockmarked hillside at a pile of pesticide sprayers left behind, long after the raid. Wild animals had gnawed through the pressurized canisters, releasing the chemicals inside. 

“They’re just these little death bombs, waiting for any wildlife that is going to investigate,” said Wengert, co-founder of the Integral Ecology Research Center, a non-profit that studies the harms caused by cannabis grows on public lands. For all her stoic professionalism, she sounded a little sad. 

For over a decade, Wengert and her colleagues have warned that illegal cannabis grows like this one dangerously pollute California’s public lands and pristine watersheds, with lasting consequences for ecosystems, water and wildlife."

Rachel Becker reports for CalMatters February 9, 2026. [2]