where can I get non-toxic foam for big cotbed bumpers?

[MareMeva]

My son regularly smacks his head on the solid wooden ends of his cotbed, either in his sleep (sleep-crawling) or when falling over while standing up half asleep. He doesn't seem to mind, but I do. I want to cover each end with a block of foam, but all I have found is sold for use in seating and is of dubious composition. I know polyurethane and polyester foam and the fire-retardants often used on them can release noxious fumes but I don't know where to go to find non-toxic foam. I did fold an old duvet in half and drape it over the cot. I tried smacking my head against it a few times and came to the conclusion that it wasn't cushioned enough. Ouch. The things we do for our children. Any ideas?

[Bearandcub]

Loving the idea of you bumping your head on purpose.

The only thought that came to mind would be to buy a reasonably priced cot mattress and cut it to suit but I have no idea how, sorry.

[MareMeva]

Thanks for the suggestion, Bearandcub. I had thought of that, but the Mothercare ones for example are foam sealed in a waterproof cover, but I would have to cut this cover, and they don't tell you what the foam inside is made of. I have contacted them with this query and they are meant to be getting back to me.