Tear gas at Portland protests raises concern about pollution

SALEM, Ore. — The presence of U.S. agents has diminished in Portland, Oregon, but city officials are still cleaning up tear gas residue from the streets, dirt and possibly the storm drains after the chemical was used frequently by both police and federal officers during more than two months of often-violent protests over racial injustice.
The Portland Bureau of Environmental Services cleaned and took samples from six storm drains last week around the federal courthouse and a building with