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Q: True or false - Plastic in the microwave can cause cancer. ( Answered 5 out of 5 stars,   2 Comments )
Subject: True or false - Plastic in the microwave can cause cancer.
Category: Health > Conditions and Diseases
Asked by: pascal1-ga
List Price: $10.00
Posted: 20 Jun 2006 15:01 PDT
Expires: 20 Jul 2006 15:01 PDT
Question ID: 739772
My mother-in-law sends countless email forwards and what have you. 
She's also quite the library of false old wives tales.  She just sent
this email to me, and I figured it was worth $10.00 for the truth.

Please provide the usual answer with references.

Thanks!!  (The "email" follows")
Cancer update -- Johns Hopkins -- Cancer News from Johns Hopkins: 

1. No plastic containers in micro. 

2. No water bottles in freezer. 

3. No plastic wrap in microwave. 

Johns Hopkins has recently sent this out in its newsletters. This
information is being circulated at Walter Reed Army Medical Center as

Dioxin chemicals 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, Dr. Edward Fujimoto, Wellness Program Manager at Castle
Hospital, 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 Corning Ware, 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, Corning Ware, 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.
-End of email from mother-in-law

Request for Question Clarification by pinkfreud-ga on 20 Jun 2006 15:09 PDT
What a coincidence. I got the same email from my mother a while back!
I checked out the story on Snopes:

Does this provide a satisfactory answer?

Request for Question Clarification by pafalafa-ga on 20 Jun 2006 15:12 PDT
Take a look at this link:

which explains (and refutes) many of the details of the message your
mom-in-law sent you.

Is that the sort of information you're looking for?


Request for Question Clarification by pafalafa-ga on 20 Jun 2006 16:48 PDT
I'm not sure of the caliber of pinkfreud's link is much better.


Request for Question Clarification by pinkfreud-ga on 20 Jun 2006 16:50 PDT
Be very careful. I've heard that paf's links are carcinogenic. :-D
Subject: Re: True or false - Plastic in the microwave can cause cancer.
Answered By: eiffel-ga on 21 Jun 2006 03:17 PDT
Rated:5 out of 5 stars
Hi pascal1-ga,

The email that your mother-in-law has forwarded to you did not
originate from Johns Hopkins.

Rolf Halden, from the Johns Hopkins Bloomberg School of Public Health
has specifically disclaimed and rebutted this email:

  "This is an urban legend. There are no dioxins in plastics.
   In addition, freezing actually works against the release
   of chemicals."

There's a lot of other solid information in his article:

   "Researcher Talks About The Risk of Dioxins"

He does warn, however, against drinking from plastics to which
phthalates have been added, as these can be endocrine disruptors in
humans and animals. Phthalates are added to make plastics flexible and
non-brittle, so you may wish to avoid drinking from bottles made of a
flexible plastic.

Regarding cooking with plastic containers, it's not quite so simple.
Rolf Halden, in the article referenced above, writes:

  "If you are cooking with plastics or using plastic utensils,
   the best thing to do is to follow the directions and only
   use plastics that are specifically meant for cooking. Inert
   containers are best, for example heat-resistant glass,

There's more detail at the "Cooking for Engineers" site:

  "Food grade plastics are made from a specific list of plastics
   approved by the FDA ... Plastics containers that are not food
   grade may leach plasticizers into food on contact."

  "Microwave safe plastics are food grade plastics (which do not
   leach plasticizers) that are known to be able to withstand
   higher than normal temperatures. Plastics that are not
   microwave safe may leach harmful substances when heated in a
   microwave oven. (There was an internet e-mail scare/hoax that
   was passed around claiming ... that dioxin (a plasticizer)
   leached out of plastic wrap onto food being microwaved. This
   is untrue since all microwave safe plastics are dioxin free.
   Saran and Ziploc both maintain that their product lines are
   completely plasticizer free. The temperatures necessary to
   create dioxin (around 1500F) are beyond the normal operating
   conditions of household and commercial microwave ovens.)"

   Equipment & Gear: Microwave Safe Containers

So, to summarise:

- Freezing water is plastic bottles does not appear to be a problem.

- If you are cooking in plastic, be sure to use a plastic that's
  labelled as microwave-safe.

- Glass and Ceramic containers are completely inert in the


Google Search Strategy:

plastic "are not microwave safe"
pascal1-ga rated this answer:5 out of 5 stars and gave an additional tip of: $5.00
Great answer, very informative, and FAST!  Thank you so much!

Subject: Re: True or false - Plastic in the microwave can cause cancer.
From: myoarin-ga on 20 Jun 2006 18:51 PDT
The big question is whether Pink is Pascal's sister-in-law.
Subject: Re: True or false - Plastic in the microwave can cause cancer.
From: eiffel-ga on 21 Jun 2006 10:25 PDT
Thanks pascal1-ga for the kind words and tip.

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