Updated

A pregnant bus driver in Wisconsin safely evacuated 37 students while they were heading to school this week before the vehicle became engulfed in flames. 

"I just told the kids, ‘let’s get off,’" Imunek Williams told WISN-TV. "I evacuated the bus, made sure everyone was off, and made them line up against a gate. And as soon as we stepped off the bus, I turned around and the bus was just — in flames." 

Williams had been driving the students — who ranged in age from kindergartners to high schoolers — along the regular route for two hours when she said she started to smell something burning. 

At first, she said she thought it was another car "but then as I started to drive more, the smell and the smoke started to get thicker." 

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Firefighters dousing bus that was on fire

School bus driver Imunek Williams evacuated 37 students on Wednesday before the bus burst into flames.  (FOX 6)

Firefighters put out the blaze on the bus, which had been headed for the Milwaukee Academy of Science.

Williams told TMJ4-TV she at first tried to call on the radio. 

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"I couldn't barely get what I was trying to say out because of the smoke was hitting me in the face in my eyes, so I was just like OK forget the radio. Just got the kids off the bus," she told the station. "I think that's when it was like my mommy instincts kicked in really fast and I was just like OK come on mom let's do it, let's get off the bus," Williams said.

No injuries were reported. Williams was taken to the hospital to have her health and her unborn baby’s evaluated and born neither suffered any injuries related to the smoke she inhaled, TMJ reported. 

Fire truck next to bus that was on fire

The cause of the fire is unknown.  (FOX 6)

She said the kids were surprised to see her picking them up the next morning after the incident.

"They actually weren't expecting to see me," Williams said. "They were like, 'Oh you're back? You didn't get burned up?' I said 'No, I'm still here.'" 

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The cause of the fire is not yet known, FOX 6 reported.