BUILDING contractors confirmed yesterday that they had opened an inquiry into allegations of migrant workers suffering “appalling” treatment at the construction site for a major new incinerator.

Unions raised concerns about the pay and conditions of some workers building a waste-to-energy plant at Wilton on Teesside, saying they had discovered pay rates being undercut.

The GMB, Unite and Ucatt unions said migrant workers were not receiving the national rates.

Reps have repeatedly called for a “forensic audit” of pay, terms and conditions for each worker at the site.

Sita Sembcorp UK, which won the contract for the project, denied exploitation.

But a statement from subcontractor CNIM Clugston said it had “launched a full and proper investigation” — though the company is unlikely to offer the spot checks and thorough run-through demanded by the unions.