As many as 30 million tires on the road are at risk of blowing out. That can cause a serious, even fatal accident. The problem? Potentially faulty tire valves.

The valves have been recalled, but you may have them on your car. Consumer Reports can help you tell if you're at risk.

Robert Monk was killed last November when his right rear tire failed, triggering a rollover crash.

The cause of the accident - a lawsuit alleges - was a cracked tire valve. One distributor of the valve has issued a recall of six models.

"If you've replaced new tires since 2006, there's a chance that your tire valves are affected by the recall," said Don Mays of Consumer Reports.

Mays checked cars in the staff parking lot and found more than one with a problem.

"At highway speeds, you could have sudden air loss, and that can be a serious problem," he said.

So how can you tell if your tire has one of these valves? It's not easy.

At a minimum, Consumer Reports says check your tire pressure at least once a month and inspect the valve for any cracks.

Flex the valve out towards the tire and rotate it, looking for any cracks along the stem. A flashlight can be helpful.

"If you do find a crack, go to your mechanic and make sure all four tire-valve stems are replaced, not just the defective one," said Mays.

To be certain that your valves haven't been recalled, have a mechanic take the tire off and inspect the valve from the inside. That's the only way to check the model number to see if your valve is part of the recall.

The six valves that have been recalled were distributed in 2006. If you've bought a new car or had your tires replaced since then, you may be at risk.

The model numbers of the six tire valves involved in the recall are TR-413, TR-413CH, TR-414, TR-415, TR-418, and TR-423.

(Copyright © 2008 Consumers Union of U.S., Inc. All Rights Reserved.)