Historical clue formulations

• Waste that's been flushed — 2025-09-16
• Underground waste — 2018-09-25
• Pollution concern — 2012-11-24
• Waste — 2010-12-05
• Waste at a treatment plant — 2008-09-08
• Waste — 2006-07-30
• E.P.A. concern — 2003-11-07