Americans consume eight billion gallons of bottled water every year.

But some scientists have started to question whether plastic bottles that hold water and other drinks might actually be harmful to consumers' health.

In a few weeks, the government will release a large-scale study about certain plastic bottles after animal tests showed that Bisphenol A affects hormones. Until then, some say they will switch over to good old-fashioned glass.

A lot of reusable plastic bottles people take to gym or work on a daily basis contain a chemical called Bisphenol A, which concerns a growing number of some scientists.

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"The effects are primary reproductive and fertility effects in both male and female organisms," said Dan Tessier, toxicologist at the University of Illinois at Chicago's School of Public Health.

To check if your bottle contains Bisphenol A, just flip it over and check the number inside the little triangle.

Any bottle with the number 3, 6 or 7 has the potential to release the chemical.

The Federal Food and Drug Administration and the plastics industry agree with scientists, who say the chemical leaches out at such low levels that it is safe.

"The toxic effects on rats were done at levels that are thousands of times higher than we are exposed to in the environment," said Dr. Gilbert Ross, medical direction of the American Council on Science and Health.

Still, a federal panel of experts said there is concern that even low levels can cause neural and behavioral effects in children and fetuses.