Does microwaving with plastic containers release toxins; will microwaved water explode?: Internet ScamBusters #278
Today we have a lighter urban legends issue for you -- legends about microwave ovens.
More than 90% of Americans own microwave ovens (44 million were sold from 2004 to 2006), but many of us don't really know how these appliances work.
It's only natural, therefore, that people are suspicious about possible side effects from devices that emit a form of radiation.
We will NOT address whether or not microwave ovens are (or can be) dangerous -- but we will tackle two specific microwave legends making the rounds.
One comes from a question from a subscriber, the other from a colleague.
Does Microwaving With Plastic Containers Release Toxins?
A ScamBusters' reader recently submitted an email, asking whether the following email was true.
~~~ Begin Urban Legend Email ~~~
Please circulate to all you know; Cancer update Johns Hopkins- Cancer News from Johns Hopkins.
No plastic containers in microwave.
No water bottles in freezer.
No plastic wrap in microwave...
A dioxin chemical causes cancer, especially breast cancer.
Dioxins are highly poisonous to the cells of our bodies. Don't freeze your plastic bottles with water in them as this releases dioxins from the plastic.
Recently, Edward Fujimoto, Wellness Program Manager at CastleHospital, was on a TV program to explain this health hazard. He talked about dioxins and how bad they are for us. He said that we should not be heating our food in the microwave using plastic containers... This especially applies to foods that contain fat.
He said that the combination of fat, high heat, and plastics releases dioxin into the food and ultimately into the cells of the body...
Instead, he recommends using glass, such as CorningWare, Pyrex or ceramic containers for heating food... You get the same results, only without the dioxin. So such things as TV dinners, instant ramen and soups, etc., should be removed from the container and heated in something else.
Paper isn't bad but you don't know what is in the paper. It's just safer to use tempered glass, CorningWare, etc.
He reminded us that a while ago some of the fast food restaurants moved away from the foam containers to paper. The dioxin problem is one of the reasons...
Also, he pointed out that plastic wrap, such as Saran, is just as dangerous when placed over foods to be cooked in the microwave.
As the food is nuked, the high heat causes poisonous toxins to actually melt out of the plastic wrap and drip into the food.
Cover food with a paper towel instead.
This is an article that should be sent to anyone important in your life!
~~~ End Urban Legend Email ~~~
Variations of this email have been traveling the Net since 2002, with later versions updated to include "corroborations" of the plastic-microwave hazard from respected medical institutions such as Johns Hopkins University and Walter Reed Army Medical Center.
Emails like this, however, prompted Dr. Rolf Halden of the Johns Hopkins Bloomberg School of Public Health to <a href="http://www.jhsph.edu/dioxins" target="_blank">issue a statement (several years ago), which says, in part:
"This is an urban legend. There are no dioxins in plastics. In addition, freezing actually works against the release of chemicals.
"Chemicals do not diffuse as readily in cold temperatures, which would limit chemical release if there were dioxins in plastic, and we don't think there are."
Dr. Halden noted, however, that through heating, "chemicals can be released from plastic packaging materials like the kinds used in some microwave meals. Some drinking straws say on the label 'not for hot beverages.'"
But he also stated that people are more at risk from drinking water that contains high bacteria levels than they are from ingesting tiny amounts of chemicals that might escape from plastics.
Will Microwaved Water Explode?
A colleague recently told us that he once reheated some risotto (a rice dish) in a microwave oven, and upon removing the plastic wrap from the bowl, the mixture "erupted" onto his arm, causing still-visible scars.
We didn't find examples of risotto-related eruptions, but it DOES seem that heating water in a microwave can cause eruptions -- under "perfect conditions."
The Food and Drug Administration (FDA) states on their site that they have "received reports in the past of serious skin burns or scalding injuries around people's hands and faces as a result of hot water erupting out of a cup after it had been over-heated in a microwave oven.
"Over-heating of water in a cup can result in superheated water (water heated past its boiling temperature), which does not appear to be boiling.
"This type of phenomena occurs if water is heated in a clean cup...
"If superheating has occurred, a slight disturbance or movement such as picking up the cup, or pouring in a spoon full of instant coffee, may result in a violent eruption with the boiling water exploding out of the cup."
If water is heated in a container with a completely smooth surface -- without any additives -- it can sometimes heat beyond its boiling point. A lack of bubbles prevents water from evaporating and keeping its temperature at 212 degrees Fahrenheit. Under these conditions, it can superheat.
When this happens, any "trigger" (like putting a spoon in the glass) may cause the liquid to violently boil, thus erupting from the container.
To avoid superheating:
- Follow the instructions in the operator's manual that comes with your microwave oven.
- Avoid excessive heating times, especially with regard to liquids.
- Leave a non-metal object in the container with the liquid, such as a plastic or wooden stir stick. This will cause bubbles to form around the object, which will then cause boiling and prevent superheating.
You can find more information on the FDA website.
That's all for today -- we'll see you next week.