Q. Dear Umbra,

I want to buy some mats for my 4-year-old to play on and do gymnastics at home. All the “nontoxic” kids’ playmats seem to be made of EVA foam, but I have the impression that almost anything “foam” (other than natural latex foam) might be either bad for the environment or bad for kids (i.e., flame-retardant chemicals). Is EVA foam OK? Any other options you would recommend? I did see some mats made of natural rubber, and of course they were very expensive.

Jaysa Z.
Boston, Massachusetts

A. Dearest Jaysa,

In a world where even the most innocent-looking products must be approached with suspicion — baby mattresses soaked in flame retardants, estrogenic sippy cups, off-gassing Barbies — it can seem that being a vigilant parent requires an advanced chemistry degree and access to molecular analysis tools. Can’t I buy one darn toy without worrying about it poisoning my kid? I imagine parents all over the world sighing in an exasperated chorus.

But no need to pick up that chem textbook, Jaysa. I’m happy to go to the mat to help you ferret out the safest products for your young’un. You’re on the right track looking for nontoxic playmats: The typical options out there (like the folding mats ubiquitous in the elementary school gyms of my youth) are made from polyurethane foam, which you’ve correctly identified as likely to contain cancer-causing, hormone-disrupting flame retardants. And they’re often covered with vinyl to boot, making them a double no-no. You are wise to steer clear.

This brings us to EVA (ethylene vinyl acetate) foam, which is generally considered to be a safer alternative to polyurethane foams. You’ve probably seen EVA foam in the form of those colorful puzzle-piece floor mats. But how safe is it, really? I’m afraid the reviews are a bit mixed on this one.

On one hand: Research out of Europe about six years ago discovered that some EVA foam kids’ mats contained a chemical called formamide. It’s rather vile stuff, linked to cancer and reproductive issues. Belgium and France quickly enacted strict limits on formamide in playmats on the market, and the U.K. also published restrictions, albeit more lenient ones. (One more strike against EVA: It is very hard to recycle.)

But on the other hand, other experts argue that although playmats can emit formamide, it’s in such small doses as to pose no real threat to tumbling toddlers. Research in Australia found that children would have to “mouth” a mat for 20 minutes (or eat four square meters of foam!) every day for the rest of their lives to do themselves any real harm. (That’s aside from the digestive complications sure to come from eating any foam, I assume.)

I don’t like to overreact to matters like this, Jaysa. But there does seem to be enough scientific concern about EVA foam to invoke the old “better safe than sorry” clause.

Since you haven’t yet invited EVA mats into your home, I’d look for an alternative. Spendy natural rubber/latex mats are one option, yes. You can also find mats made from cork, organic cotton, and nontoxic polyethylene foam, though you’ll have to judge if they’re tough enough for a 4-year-old’s handstands and somersaults (versus an infant’s gentle explorations). Or how about using several layers of comforters or quilts on the floor? That might provide just the cushion your budding gymnast needs.

Another factor to consider about EVA foam mats: Research shows that off-gassing is most acute when mats are brand-new, with formamide emissions dropping considerably within a month. So you could look to buy such playmats used, or keep new ones outside and away from your kids for a month.

And if all of this discussion over just one of the average kiddo’s many accessories has you exhausted, don’t forget: Wooden blocks, cornhusk dolls, and string-and-button buzzers worked just fine for our great-grandparents, and I daresay they’re due to come back in style.