Biffa's Houghton Quarry landfill site in Tyne and Wear has attracted the attention of the European Parliament's petitions committee following a complaint by campaigners.
Houghton Residents Against Toxic Site complained to the parliament earlier this year. The committee's chairwoman, Erminia Mazzoni, has now written to the Environment Agency chief executive Paul Leinster about the site, at Houghton-le-Spring near Sunderland.
The MEP's concerns include groundwater protection. In particular, they raise the issue of significant levels of ammonia close to the site last December.