Minutes before two pileups killed 10 people on a highway shrouded in fog and thick smoke from a brush fire, the Florida Highway Patrol had reopened the always busy six-lane interstate after an earlier serious accident. A sergeant and lieutenant determined after about three hours that conditions had cleared enough for drivers, but visibility quickly became murky again, officials said Monday.

The Florida Highway Patrol said Monday that conditions were clear enough to reopen Interstate 75 before a deadly pileup early Sunday, but Gov. Rick Scott is ordering an investigation.

Two people were shot and wounded about midnight Saturday at the South Florida Fair, leading to a lockdown at the fairgrounds that kept thousands of people from leaving for up to an hour, according to thePalm Beach County Sheriff’s Office.