NASCAR has fined Tony Stewart $35,000 for criticizing the series about a potential safety hazard during races.

The fine issued Thursday falls under NASCAR's new behavioral policy and comes a day after the three-time champion warned that a driver is going to get hurt if the series doesn't start policing pit stops for missing lug nuts.

There's been a rash of loose wheels the last two races because some teams are not applying the maximum five lug nuts during pit stops. By skipping one or more, a team can have a faster stop and gain better track position.

Loose wheels can create accidents or cause a tire to fall off a car. NASCAR stopped officiating missing lug nuts last year.