York Salvage Yard Fire Unified Command responders employ underflow dams, boom and skimming techniques to remove oil and waste from an unnamed tributary that leads to the Codorus Creek, March 3, 2026. Underflow dams are a key tool used by oil spill responders to contain oil, fuel, and floating contaminants in streams, ditches, and creeks during environmental cleanup operations. They work by allowing cleaner water at the bottom to pass through a pipe while trapping floating contaminants behind the dam for recovery. These structures are critical for protecting water sources and mitigating environmental damage in small-scale, remote, or hard-to-reach locations. U.S. Coast Guard photo by Chief Warrant Officer 3 Timothy Tamargo