BALTIMORE -- Johns Hopkins researchers have responded to an e-mail warning against freezing water bottles.

A recent e-mail hoax claims Hopkins scientists warned people that freezing plastic bottles releases dioxins into the water. But the researchers say that's entirely false -- they said freezing plastic water bottles will not expose people to dangerous chemicals.

According to Dr. Rolf Halden, of the Johns Hopkins Bloomberg School of Public Health, freezing actually works against the release of chemicals and scientists are not even sure plastics contain dioxins.

However, Halden does warn that another group of chemicals that are used to make plastic less brittle can be released if you place them in hot water or heat them in the microwave.

But Halden stresses that people should not be afraid of drinking water and that "you are more likely to suffer from the adverse effects of dehydration than from the miniscule amounts of chemical contaminants present in your water supply."

He also said people should be more concerned about the quality of the water they drink more than the bottle from which they drink it. Although people tend to assume bottled water is the safest route, Halden said city water is much more highly regulated and monitored for quality.