Cleanup crews hauled away 300-pound barrels of chlorine compounds, and officials met to assess the damage of a four-day fire that destroyed a chemical factory and forced the evacuations of 25,000 people.

Residents who fled their homes as poisonous yellow-green fumes wafted over the state's third-largest city were allowed to return Monday after firefighters neutralized leftover chemicals in the Advanced Laboratories plant.

About 275 people, including 22 firefighters, were treated for respiratory problems and chlorine burns as explosions peppered the century-old mill housing the factory.