Dumping of production materials, including toxic waste, resulted in significant contamination of the Irish Steel plant site, and increased the size of Haulbowline island by 9 hectares (22 acres).

Campaigners, including Erin Brockovich, pushed for action by the state,[3][4] and €61m was allocated to clean-up the site and to redevelop it as a park.

[17][19] Reports of land and asset sales, prior to closure, led to some accusations of "asset-stripping" by the parent company.

[20] One such asset disposal, in the months prior to closure, involved the sale of a 30-acre site (for an undisclosed sum) to build a hazardous waste incinerator to the "fury of local residents".

[25] The "East Tip" expanded over several decades to include 650,000 cubic metres of waste, extending eastwards from Haulbowline's naval dockyard.

[30] According to the terms of planning permission, received by Irish Steel in 1981, there were no controls placed on the material that could be dumped or on protections required to prevent leachate into the harbour.

[37] While the Environmental Protection Agency had attributed €15.9m of the projected site cleanup costs to Irish Ispat (formerly Irish Steel), the High Court dismissed a claim by the state to have the company's liquidator cover the cost of making the site environmentally safe.

[38] The Irish government was later threatened with legal action by the European Commission, for a failure to meet its obligations under the Waste Framework Directive.