NEWPORT, Mich. As many as 50 Fermi II workers were evacuated today from the auxiliary building that sits between the nuclear plant s reactor and the building that houses its steam generators.

Fire alarms apparently were errantly triggered on and off by the region s extreme humidity, said Viktoria Mitlyng, Nuclear Regulatory Commission spokesman.

The heat index in Monroe, near where the plant is located, was the highest in the Toledo area today at 107 degrees from 1 to 3 p.m. The index is a combination of heat and humidity as measured in shaded areas with light winds.

No smoke or fire was detected, nor were any injuries or property damage reported.

However, the fire protection systems activated the release of a fire-suppressant gas, carbon dioxide, in one part of the affected building. The gas had to be vented before employees were allowed to return, she said.

Eileen Dixon, Detroit Edison Co. spokesman, said the plant s fire brigade responded. She said the utility notified the NRC of an unusual event in progress at 1:44 p.m.

Barring any complications in getting the fire-suppression event resolved, the utility hopes to have Fermi II s reactor back at full power late Tuesday night. Power ascension was expected to reach 20 to 25 percent of the reactor s capacity tonight, enough to have the plant putting electricity back on the grid, Mr. Austerberry said.

Read more in later editions of The Blade and toledoblade.com

First Published August 1, 2006, 1:32 a.m.