There's a fairly long list of things that can be absorbed through the skin. LSD and THC can both be absorbed, however there is limited systemic intake, so you need a lot, or the right conditions. This is the same for many things.

This is why as a former HazMat Medic, I would always rinse people with cold water. Close the pores, decrease circulation (not because I'm a sadist).

Warm conditions, certain carriers (as mentioned above) as well as general skin condition and thickness of epidermal layer also play a big role.

I was always taught that if you don't know if you should be wearing gloves/suit/respirator....the answer should default to yes.