Don't lick the walls!

Sources:

-       https://www.mayoclinic.org/diseases-conditions/lead-poisoning/symptoms-causes/syc-20354717

-       https://www.pbs.org/newshour/health/how-a-doctor-discovered-us-walls-were-poisonous

-       https://nlm.nih.gov/exhibition/thisleadiskillingus/index.html

-       https://www.epa.gov/archive/epa/aboutepa/lead-poisoning-historical-perspective.html

-       https://en.wikipedia.org/wiki/Lead_poisoning

-       https://www.cbsnews.com/news/lead-poisoning-hemorrhoid-treatment-california-death/

-       https://en.wikipedia.org/wiki/Flint_water_crisis