Workers at a Nottinghamshire power station have walked out over safety fears after a colleague was injured when scaffolding collapsed.
Union officials said the scaffolding at Cottam power station near Retford was installed by Portugeuse workers.
A construction worker was badly injured when staging collapsed on Monday.
"We want to make sure the work done by these workers is checked to make sure it is up to British standards," Amicus representative Jim Simms said.
Foreign labour
A health and safety investigation is under way into the accident.
Mr Simms, regional officer for Amicus, said the union is involved in an internal investigation into the accident that the company has started.
"We are concerned about the involvement of foreign labour - we think that safety standards have dropped and we hope the HSE inquiry will look at that."
A EDF Energy spokesman said: "Safety of staff is of paramount importance to us."
He said some workers did leave the site on Tuesday, but most were back at work on Wednesday.
The worker who was injured was part of a construction crew installing flue gas desulphurisation units or scrubbers, which removes sulphur dioxide from emissions.
Amicus spokesman Paul Corby, said: "Only last week the trade unions were at the Department for Trade and Industry, stating our safety concerns regarding unregulated foreign labour."
The union says the Posted Workers Directive, which allows foreign workers who are not trained in the same safety standards as those in the UK to work in this country, is contributing to an increase in construction accidents.