Four truck trailers loaded with magnesium burn early Tuesday at the MagReTech Inc. plant on Sandusky County Road 177 in Bellevue, Ohio. Fire officials said the cause is under investigation, but it is believed lightning sparked the blaze. The fire was allowed to burn out because water can’t be used on magnesium, a dispatcher said. The fire was reported about 4:45 a.m. and brought under control within five hours. Bellevue schools were closed because of air-quality concerns.