If crews know hazardous materials are involved, they must investigate to determine what substances they are.
When deciding whether or not to inform the public and evacuate, they rely mostly on published values of toxins from the government and incorporate a few other factors in their decision.
"We look at nearby properties. Is there anybody living in the area? Is there residential homes in the area? Is it late at night are they home in bed, asleep, not knowing this is going on?" says Lt. Greg Goettsch of the Abilene Fire Department.
Fire crews determined that no evacuations were necessary during this fire Thursday morning.