My most recent article in the June issue of Natural Life Magazine is about using expanded polystyrene (EPS) for crafting, the last in my series about reusing what would otherwise be waste plastics for crafting purposes. "STYROFOAM (tm) Brand Foam by Dow" is the proper way of writing out the trademarked term for the most well known and oldest brand of expanded polystyrene foam. The packaging I used in my project was not the Dow material - unfortunately for me because they pay for published pieces using the craft products. For a description and how it differs from other EPS products, go to the STYROFOAM(tm) Brand Foam website.
Some NLM readers have expressed concerns.
I thought long and hard about doing EPS (I'm now going to avoid the trademark for most of this post) because it really does contribute to the problem of litter in the environment - much of which ends up in the ocean. There has been much discussion about the safety of EPS food containers, most especially about hot food and reheating in the microwave and leaching of chemicals into food.
Here are a couple of links to that information:
Food grade packaging & testing guidelines:
FDA Food Ingredients and Packaging page
Here are some useful pages on identifying and safely using microwaves and plastics:
Harvard Medical School
Personally, I don't really trust my rather old microwave and whatever internal thermostat it uses, so I avoid the question by not microwaving EPS containers regardless of the label. I can't be certain the temperatures are staying in the designated safe zone to avoid melting, there has been an odd taste sometimes in the dim and distant past, and I have pyrex dishes at home that are better. I never think the EPS cups look clean when I see them out and about. I'm not thinking the grubbiness is necessarily toxic chemical dust, just ordinary-dirt-from-a-warehouse dust, or sitting-in-a-cardboard-box-for-a-while dust. Blech. I have a metal travel mug I tend to carry around with me.
There may be some confusion about off/outgassing of EPS at normal temperatures. According to the MSDS that I have found, the outgassing is very minimal and the products like foam coolers or craft balls are safe when used properly by the consumer. By properly I mean don't burn, melt or dip the stuff into solvents.
Sometimes the confusion arises because the word "foam" is used for more than one kind of product from more than one source chemical. Polyethylene foam can outgas small amounts of odorless flammable hydrocarbons. It should not be stored in confined spaces where a spark might occur. I remember when there were a lot of warnings around to do with foam insulations and mattresses. These are often made of Polyurethane foam, another highly flammable foam that gives off an assortment of nasty gases when heated or burnt, and can create irritating dust.
Here is a very nice article talking about safe use of a number of arts and crafts materials, based around their use in model railroading by adults. It quotes several MSDS sheets with links, and is a rather nice summary. Scroll down for the section about foams.
The blowing agent used for expanding polystyrene is usually a hydrochlorofluorocarbon, although that is changing. If there is any outgassing, this is what is outgassing, not the styrene - not toxic but not good for the ozone. Remember when we all stopped using hair sprays in the early 1980's to protect the ozone? (Am I showing my age?)
However, this brings me to the very recently released National Toxicology Program 12th Report on Carcinogens.
Styrene, one of the main original components of polystyrene, has newly been classified as "Reasonably anticipated to be a human carcinogen". This falls short of the most damning designation "Known Human Carcinogen". That list is also really worth reading! (Scroll down and click "Access Report Contents".)
To be honest, I tend to assume that all industrial chemicals could be "reasonably anticipated" to be a human carcinogen, especially at high levels of exposure. (Some people are affected by even slight exposures if they have Multiple Chemical Sensitivities. I doubt these folks are doing much crafting with even innocuous non-toxic paints and glues, or natural products like botanical dyes or essential oils.) EPS itself is pretty much inert unless you start burning or melting it with high heat or chemicals, or grinding it into dust.
The commercial foam cutting tools that rely on heat are supposed to melt it well below the thresh-hold heat for burning the foam. Please do your own research on those. I don't own one, but I've seen the little puff of dark smoke when the hot wire first touches the foam and I'm just not sure - so I cut with a serrated edged knife instead IF needed. However maybe I'm being paranoid. Here's an MSDS from Dow, referring specifically to the STYROFOAM (tm) Brand Foam as used in home insulation:
"Upon burning the product generates dense black smoke with small amounts of hydrogen bromide, -chloride, and -fluoride. Studies have shown that the products of combustion of this foam are not more acutely toxic than the products of combustion of common building materials such as wood."
Right, because wood smoke is so good for you. Don't stand downwind of a house on fire. But back to the issue at hand.
I have read the entire section of the report dealing with Styrene, and I am slowly making my way through the other information because it is fascinating. Also included are letters and input disputing the findings in the report. I encourage you to read the report yourselves, rather than rely on simplistic interpretations in the media alone, some of which have excessively alarmist headlines or are too dismissive. Some of the articles also conflate one chemical with another just because the study results are included in the same report. The studies themselves are not connected. (But still worth reading about.)
Here are my conclusions:
Factory workers in styrene manufacture and related industries (in Europe and US especially) are exposed to very high concentrations of styrene, orders of magnitude greater than the general population, and are at statistically relevant higher risk for certain cancers. Styrene is used in many, many products some of which are more noxious than others. These are slowly becoming ubiquitous.
The greatest exposure to styrene in the non-occupational (ie not manufacturer/factory workers) population is from cigarette smoke which is greater than the exposure from all other sources combined.
I think the strongest, immediate conclusion we can draw from this report is that the factories need much more stringent health and safety regulations to protect workers!
Here's some of what I talked over with Wendy, the editor of NLM.
Quoting the report:
Here are my recommendations:
Here is a free MSDS search engine.