It's gross, but it's not dangerous.
I think every parent has been in this situation – when you squeeze out a bath toy that's full of water, only to squirt bits of black mold everywhere. It's always a bit shocking, and definitely disgusting, and has resulted in more than a few toys going straight into the trash in my household.
But according to Jenny Marder, writing for the Washington Post, there is less cause for concern than most parents may think. Sure, mold isn't great, and we should all try to minimize our exposure to it, but as Michael David, professor in the University of Pennsylvania's Division of Infectious Diseases, told Marder, he's never once seen a healthy person infected by mold that has come from bath toys or other children's products.
"The reason I think the subject hasn’t been explored much is that it hasn’t come up as a problem. People almost never come in with an infection caused by the types of mold that grow on a household item."
David's opinion is backed by Susan Huang, a medical director for epidemiology and infection prevention at the University of California. She has two kids herself and says that healthy children's immune systems can handle breathing or even accidentally eating mold spores. "Nothing really happens — other than people being somewhat disgusted."
That's not to say you should just let the mold run rampant. It's still smart to take steps to keep it in check. Marder suggests boiling toys to sterilize them or filling in the hole in the bottom of plastic squeeze toys with a hot glue gun to prevent water from entering. You could also cut it larger to be able to scrub out the inside.
At my house, we've given up on soft plastic toys for reasons other than mold. They contain toxic, hormone-disrupting chemicals like PVC, phthalates, and BPA, and I'd prefer my kids not to handle that. Instead, they take hard plastic toys into the tub, like Playmobil, LEGO, wind-up animals, and drinking cups, which dry quickly on a towel once they're done their bath and aren't as prone to mold growth.