CFCS
| Date | Clue |
|---|---|
| 2021-08-01 | Ozone-harming compounds, for short |
| 2016-07-31 | Ozone destroyers, for short |
| 2015-08-06 | Ozone-destroying chemicals, for short |
| 2013-10-25 | Ozone destroyers, for short |
| 2011-10-14 | Ozone destroyers, for short |
| 2010-02-25 | Regulated pollutants, for short |