Plastic in the Dishwasher

In my last post for 5 Minutes for Going Green I explored the environmental impact of using the dishwasher vs. washing dishes by hand. You may recall that there was not a clear winner, but as someone who hates washing dishes, I declared that I would continue using the dishwasher myself. When the answer isn’t clear, I tend to make the decision based on personal convenience.

After that post went up, one of my friends got in touch and asked me about washing plastics in the dishwasher. She has been debating the topic with her husband. I didn’t know anything about the safety of plastic in the dishwasher myself, so I decided to look into it. The truth is, we use rather a lot of plastic in our daily lives. More so than I would like, but it’s hard to beat its durability when you have small children. Once the issue had been raised, I wanted to get some answers for my own peace of mind, too.

I ran some internet searches, and did some reading. A lot of sources talked about the obvious damage that can happen when you put plastic in the dishwasher. Flimsy plastic take-out containers often shrink and warp after a single wash, for example. This is why many plastics are labeled ‘top rack only’ – by putting more distance between your plastic and the dishwasher’s heating element, you reduce the risk of obvious damage.

Even when the damage isn’t obvious, though, plastics may be experiencing dishwasher-related wear and tear. At high temperatures in the dishwasher chemical reactions can occur, invisible stress can happen, and plastics can degrade. Appliance Magazine studied plastics in the dishwasher, and concluded that polycarbonates stood up the best. However, polycarbonates contain BPA, a chemical that is linked to developmental, reproductive or immune effects, especially in children.

Heat causes BPA to leach at much higher rates, causing concern over washing plastics in the dishwasher. And not just BPA, other chemicals, too. Dishwashers use very hot water, vigorous agitation and harsh detergents. Taking all this into account, some people recommend that we keep plastic out of the dishwasher altogether. Or, to take it a step further, avoid plastic coming into contact with our food, period.

This information gives me pause. I am working on phasing plastic out, but I still have a long way to go. In the meantime, I am re-considering how I wash my plastics, and how I use them. Plastic dishes are convenient, no doubt about it. But a little bit of inconvenience is a small price to pay in comparison to my fears that I may be exposing my children to toxins leaching from their cups.

What about you? Do you wash plastics in the dishwasher? Why or why not?

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You can catch up with Amber’s regular adventures in dishwashing and parenting on her blog at

6 Responses to Plastic in the Dishwasher
  1. […] Plastic in the Dishwasher […]

  2. Melissa King
    June 30, 2010 | 3:25 pm

    Just a quick comment on your message about plastics in the dishwasher. Did you know that plastic also degrades in microwave ovens? Use caution in placing any plastic containers in the microwave for heating foods because the same problem of harmful chemicals being released into foods that someone will consume.

    As for me, I wash all plastic containers by hand and don’t put any in the microwave. Better safe than sorry!

  3. […] the cups they get at restaurants and theme parks).  However, I began to hear whisperings about plastic degrading due to high temperatures in dishwashers and that was enough for me to eventually say the heck with […]

  4. Richard
    April 9, 2011 | 8:27 am

    Hi Amber, what about the plastics that most dishwashers are made of inside ie on the racks ect?


    • Amber
      April 9, 2011 | 12:11 pm

      It’s a good question, and I don’t know the answer. Although I will point out that we’re not eating off of those surfaces, so the issues are a little bit different.

  5. Michel Haussi
    April 30, 2011 | 1:04 am

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    Plastic Plates