Gas mask with filter canister worn at demonstrations in Ferguson, Missouri

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2,335 American Gas Mask Stock Photos, High-Res Pictures, and Images - Getty Images

Subject of iconic Ferguson, Mo., photo talks about anger and excitement that led him to throw tear gas canister – New York Daily News

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German Gas Mask, Artifacts

A black gas mask with a filter is worn on a mannequin. Bottom up view Stock Photo - Alamy

Protests over Ferguson continue

Historical gas mask hi-res stock photography and images - Page 3 - Alamy

American gas mask hi-res stock photography and images - Page 2 - Alamy