Safe wood sealant? (swing/play sets)

We're looking at wood play sets for our daughter and are trying to figure out which ones are safe. Obviously pressure treated wood is out. The redwood sets we've seen say they are water sealed and stained, but not with harmful chemiicals. I'm not sure I buy that! For example, Rainbow playsystems offer a can of sealant for yearly maintenance that contains Ethylene Glycol Monomethyl Ether. From what I could see, that's not a risk-free chemical. Or is it a case that it's safe once cured?

Any suggestions on how to really verify if these playsets are safe or not?

I apologize if I posted this in the wrong forum!

Thanks,
Kim