Anyone who’s heated something up in the microwave has probably wondered about possible health effects. One common email exploits this fear by quoting information allegedly contained in a newsletter from Johns Hopkins University, adding that the “information is being circulated at Walter Reed Army Medical Center.” Various versions of this email say a Dr. Fujimoto from Castle Hospital was on a TV program warning that heating plastic in the microwave or freezing water in plastic bottles releases toxins, like dioxin and DEHA.

In August 2004, the email took on new life when the name of an American Cancer Society staffer at the bottom of the email seemed to give the story real credibility.

In 2007, a "cancer update" email quoting a newsletter purportedly from Johns Hopkins Hospital with lots of other false claims was added to the email.

This email has its roots in a January 2002 appearance on KHON-TV, Honolulu by a genuine person, Dr. Edward Fujimoto, who apparently made these claims. The US Food and Drug Administration (FDA) on its Web site does say substances used to make plastics can leach into foods. But the agency has found the levels expected to migrate into foods to be well within the margin of safety based on information available to the agency. As for dioxin, the FDA says it “has seen no evidence that plastic containers or films contain dioxins and knows of no reason why they would.”

As to the information added in 2007 and attributed to Johns Hopkins Hospital, Johns Hopkins officials say they did not publish the information nor do they consider its contents valid.