( CNN ) -- Crews in North Dakota were testing the air Tuesday morning for any dangerous fumes a day after two trains wrecked , sparking a large fire . Crews are testing the oil near Casselton , North Carolina . They are testing for any toxic fumes . A car accident on Monday created an oil spill .
Crews are testing the oil near Casselton , North Carolina . They are testing for any toxic fumes . A car accident on Monday created an oil spill .