Historical clue formulations

• Banned chemical contaminant, for short — 2024-08-15
• Banned pollutant, in brief — 2021-02-08
• Banned pollutant, for short — 2020-01-12
• Banned pollutant, in brief — 2018-05-14
• Chemical contaminant, for short — 2018-02-24
• E.P.A.-proscribed compound, for short — 2013-05-13
• Banned organic compound, for short — 2012-06-04
• Environmental pollutant, for short — 2011-03-20
• Toxic chemical, for short — 2010-01-24
• Toxic pollutant, for short — 2009-04-29
• Outlawed pollutant, for short — 2007-08-26
• Chem. contaminant — 2001-05-07
• Wildlife threat, briefly — 2000-03-18
• Chem. pollutant — 2000-03-14
• Toxic compound, for short — 1999-03-22
• Banned chemical compound — 1994-09-01
• Toxic compound, for short — 1994-03-26