CHARLOTTE, N.C. -- Labels recently became a part of my everyday life.

Too much MSG in this.

There's BPA in that.

And what the heck is butylated hydroxyanisole?

Now imagine you're an athlete in today's world of supplements and energy drinks that many feel are necessary to keep pace with the competition. Imagine you digest something that is contaminated with substances that are not on the label.

It happens more than you think, according to Dr. Don Catlin, considered the "father of drug testing in sports," and other experts.

The International Olympic Committee found in 2001 that almost 25 percent of 600 over-the-counter nutritional supplements tested were contaminated with non-labeled substances at levels that could lead to a positive test.

While those numbers have shrunk substantially thanks to education and awareness, the Food and Drug Administration -- which put in manufacturing standards for supplement companies in 2010 -- sends a warning letter to one in every four supplement makers for manufacturing violations.

"Yeah, it's a huge problem," said Catlin, co-founder and president of Anti-Doping Research and founder and the former director of the UCLA Olympic Analytical Lab. "It's an everyday problem."

Which brings us to suspended Sprint Cup driver AJ Allmendinger. He said he tested positive for a stimulant -- NASCAR does not reveal the results to the media or public -- but claims he never "knowingly" took a banned substance. He said he believes it could have come from a supplement or over-the-counter drug -- perhaps even the Fuel in a Bottle energy drink he endorses -- so he has gathered everything to be tested.

Blaming contamination often is the first excuse for offenders guilty of taking a banned substance. Contamination also is the blame for many positive tests.

This isn't something new to sports.

In 2002, Olympic bobsledder Pavle Jovanovic claimed he unknowingly ingested a multivitamin, nutrition bar or protein powder that contained traces of the steroid norandrostenedione, which resulted in a positive test.

In 2004, Olympic swimming hopeful Kicker Vencill won a lawsuit against a supplement manufacturer after claiming a contaminated vitamin caused him to test positive for steroids.

In 2009, Philadelphia Phillies reliever J.C. Romero was suspended for the 50 games for a positive test for a diet supplement that contained a legal testosterone booster the pitcher said he was unaware could cause a positive test.

There's plenty more.

This isn't to suggest innocence or guilt for Allmendinger, whose career is on life support until results of Tuesday's "B" sample urine test are revealed. Ultimately, Allmendinger and any athlete is responsible for what he takes.

But it does make you think. And it is a concern in sports.

It should be a concern in NASCAR, whether with Allmendinger or another driver in the future. Unlike 10 or more years ago, fitness has become a big part of the sport for drivers. Many take supplements today like Richard Petty used to take a Goody's Headache Powder.

That puts them at risk.

Some organizations have programs in place to help prevent that. Hendrick Motorsports makes supplements available at the facility known to be cleared by NASCAR.

If there's a question about a supplement, drivers and crew members are instructed to seek direction from NASCAR.

Unfortunately, not all teams are so structured -- or have the finances to be.

"When it comes to the drug testing population and using supplements, I would take the position of buyer beware," said Ed Wyszumiala, the general manager for NSF International that writes dietary supplement standards and certifies products against those standards for the NFL, MLB, PGA, LPGA and other professional sports.

"It's like anything associated with [NASCAR], you always go through additional testing or quality control checks to make sure parts and tires and everything has been tested and tested and tested. When using these nutritional products, the same thing should be used for these athletes."

But as we see with car parts, bad ones sometimes get through.

NASCAR doesn't have a company specifically assigned to supplement quality control. It leaves it up to the drivers and crew members to ask the right questions and consult with Dr. David Black of Aegis Laboratories in Nashville, Tenn. Aegis does the drug testing for NASCAR.

"We're very comfortable with our stance on supplements," said David Higdon, NASCAR's managing director of integrated marketing. "Ultimately, the members tested all are responsible for what goes into their bodies.

"Our rule book contains language pointing to the warning signs of what some supplements contain, and to avoid all supplements that advise non-use if one is subject to a drug-testing program. NASCAR members are encouraged to contact Dr. David Black … if they have any questions pertaining to supplements."

NASCAR's list of banned stimulants includes Amphetamine, Methamphetamines, Ecstacy, Eve (MDEA, MDA, PMA), Phentermine and other Amphetamine derivatives and related compounds.

But because you have a liost doesn't make things foolproof. Sometimes labels don't tell us everything in a supplement or energy drink. Sometimes manufacturers accidentally contaminate one product with something from another made in the same vat, if that vat wasn't properly cleaned.

"I got really bothered by this whole thing 10 years ago," Catlin said. "We kept running into Olympic athletes who were showing up with positive tests. I interviewed lots of them. They were really innocent in the sense they were not doing it deliberately. It took a long time to clean up.

"This is all sort of new to NASCAR. We don't find Olympic athletes buying something off the shelf anymore. They know better. That may have to happen in NASCAR."

Maybe Brad Keselowski had the right idea. He said drivers -- athletes in general -- shouldn't take any drug or supplement to help with performance regardless of legality or their need for medical reasons. He faced it just last last year with a foot injury.

"It's my personal belief that nothing should be allowed -- nothing," Keselowski said. "I don't feel like you should be able to take Flintstone [vitamins]. I think you're race car drivers; you should have to overcome it.

"I think it's a bunch of bull---- that people are allowed to take supplements or any of those things."

That's a hard line not many will agree with or follow.

But why take them at all? A stimulant would give a driver a competitive advantage in terms of endurance and focus.

"Let's use this year's Daytona 500 with all the delays, how long it took to complete the race in terms of a normal running,"...