Notable events
| Start year | End year | Sector | Information | Impact |
| 1990 | 1993 | Chemical Industry | Abatement and change of process for production of chemicals | Decrease in emissions |
| 1999 | 1999 | Metal Production | Abatement and change of process for secondary aluminium production | Decrease in emissions |
Hexachlorobenzene (HCB) is an organochloride. It is formed as a by-product during the manufacture of other chemicals. It was widely used as a fungicide. Due to HCB's persistence in the environment, it has been banned globally under the Stockholm Convention on persistent organic pollutants. Very little information is available on the health effects of HCB via inhalation, however, the lungs may be affected by repeated or prolonged exposure. It is also considered to be a possible carcinogen. Since the most significant sources of HCB emissions in 1990 no longer use processes that emit HCB, UK emissions have reduced by 99% between 1990 and 2021. By far the largest source of emissions for the years 1990-1998 was related to the use of hexachloroethane (HCE) in the aluminium industry, however the sector stopped using HCE after 1998 so HCB emissions from this source were eliminated from 1999 onwards. The last remaining production plant for chlorinated solvents closed in 2009, and so emissions from this major source also ended then. As these once-important sources have disappeared other sources, such as the burning of municipal solid waste (MSW), for public electricity and heat production and the use of certain agrochemicals, have been left to become the main UK sources, accounting for 78% and 19% of emissions in 2021 respectively.