PORTLAND, Maine — The Portland Fire Department responded to a carbon monoxide issue at the InterMed building on Marginal Way in Portland Friday afternoon.

Officials say four people were transported to the hospital, but they all tested negative for carbon monoxide poisoning.

The building was evacuated. Officials originally only closed the seventh and eighth floors, but they have since closed the whole building out of precaution.

Fire officials tested the entire building, but they could not find any carbon monoxide readings. An air quality specialist is on the way to assess the building.