The Washington State Department of Transportation is looking into whether systems in the new State Route 99 tunnel operated as designed Wednesday morning after operators had to manually turn on fans to clear smoke and haze.

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It happened during the first day of real traffic in the new tunnel, which opened Monday during a snowstorm when few people were on the road.

A KIRO 7 crew standing outside the north portal late Wednesday morning noticed haze and smelled exhaust coming from the tunnel.

KIRO 7 assignment editor Brooke Pinkston also saw it as she drove.

“I did notice a haze at the bottom of the cars this morning going through the tunnel,” Pinkston said.

She pushed her air recirculation button.

“I didn’t want to breathe it in.”

WATCH: A test drive through Seattle’s new tunnel

WSDOT officials say a crew in an incident response vehicle also saw the haze and reported it to tunnel operators, who switched on the fans.

Fans are designed to switch on automatically when sensors note an uptick in emissions.

Most of the time, fans are not needed in the tunnel because traffic pushes the air using what’s called the piston effect.

The large yellow stacks at the ends of the tunnel are to clear the air in serious incidents like car fires.

Written by Graham Johnson