Flammable cargo will be prohibited from traveling in both directions of I-90 inside the Mount Baker tunnel and the Mercer Island lid until 4 p.m. Thursday, Sept. 19. The same restriction will go into place from the evening of Friday, Sept. 20 through the morning of Saturday, Sept. 21. During the closures maintenance crews from the Washington State Department of Transportation will work on the fire suppression system. Drivers needing to transport flammable materials across Lake Washington must use alternate routes such as I-405, State Route 520 or 522. Drivers transporting flammable materials on westbound I-90 must exit at Island Crest Way on Mercer Island. Eastbound drivers transporting flammable materials must exit at Rainier Ave South in Seattle. Drivers can check travel conditions by going to the Seattle traffic website or by dialing 511.