Protesters against police racism and brutality were hit with tear gas not only in the United States, but also many other regions of the world protesting in solidarity.
Stunning amounts of tear-gas have been noted to have been used in Seattle, Portland, and Olympia.
On the 27th of July in Portland, federal agents and police were found to have been using a new kind of tear gas, that has 3 carcinogens in it and was first used against the protesters against the Governor in Puerto Rico.
A detailed report on the tear gas can be read here: Defense Technology 1026 – Triple-Chaser Separating Canister CS – US
The carcinogens include lead salts, methylene chloride, and hexavalent chromium. All are known to cause cancer, and lead salts are also known to cause birth defects or other reproductive harm.