Yes! Any chemical substances can potentially enter the bloodstream by being licked and absorbed through the oral mucosa or the lining of the mouth .

Yes, it is dangerous. However, it all depend on the quality absorbed in the GI tract. Now, the amount licked could be inconsequential. The patient needs to be tested for the levels of those toxic substances in blood. Thank you.

Precaution is your best recommendation. Absolutely avoid bringing any potentially toxic substances from work into your home! Yes, "licking" can potentially enter a person's bloodstream, but its affects will depend on the substance, dose, frequency, etc.

Licking a chemical is like licking salt and some of will get absorbed and enter his bloodstream.

You did not describe or mention the toxic chemicals that are involved. But there are diagnostic tests that measure environmental toxins including heavy metals. Ask your doctor to order tests to measure the specific toxins you are concerned about.