Partner thinks our toddler gets hyper after touching red food coloring. Can you help me find evidence that skin absorption and ingestion are not the same?

I’m hoping that someone with more scientific knowledge can either provide or point me in the direction of useful resources to help back my side of this argument. Or prove me wrong if that’s the case.

I’m not trying to argue whether red food dye is bad. I know the FDA recently banned Red #3 and many people, especially parents, avoid Red #40 because of its effect on children. My husband’s son from his first marriage has autism, and they avoid Red #40 because I guess it really affects his mood and behavior. I’m fine with this and happy to accommodate his dietary needs.

My issue is that we also have a 2.5 yr old and I love doing sensory bins and science experiments, like ooblek or slime, but my husband seems to think that simply touching red food dye is enough to impact our toddler’s behavior. I’ve tried to explain that there is a big difference between ingesting something vs touching it. For example, we don’t stay hydrated by standing in the rain, we have to actually drink a glass of water. But he’s holding strong on his opinion.

I haven’t been able to find any helpful articles related to skin absorption and red food dye, minus a few mentions of Red #3 in cosmetics, and a handful of blogs and facebook posts that are clearly not backed by science. So if anyone here knows more or has read anything about this, please share! Or, please correct me if I’m the one in the wrong.

My husband is well educated and highly intelligent, which is why this argument is really driving me crazy. I’ve tried to explain that there’s a 2.5 yr sleep regression and 2 yr molars…but he’s convinced that our science experiments with a few drops of food coloring are the reason why our toddler won’t sleep like he used to.