The exposure of two electricians to toxic chemicals at a Civic office building will be investigated by ACT work safety authorities.
Meanwhile, unions described the incident as ''extremely concerning'' and raised fears other older buildings could be contaminated.

The two workers were hospitalised after being sprayed with fluid when a light fitting they were replacing exploded in the computer room on the eighth floor of Canberra House.

The fluid was contaminated with polychlorinated biphenyls, or PCBs, a toxic chemical that can cause skin rashes and, in severe cases, damage to the liver and nervous system.

Both electricians were taken to Canberra Hospital for monitoring.

The Electrical Trade Union told The Canberra Times that PCBs have not been used in light fittings for decades.

The union said it was deeply concerned by yesterday's incident, and the union's NSW-ACT assistant secretary Neville Betts demanded the owner of Canberra House search light fittings throughout the rest of the 11-storey building.

Mr Betts also said a broader investigation into other old buildings around the ACT might be necessary.

The contaminated liquid should have been identified during major campaigns to remove PCBs from buildings in the 1980s and 1990s, he said.