If you live in the United States and have bought or rented a place, you have almost certainly run across one of these. A classical case of damage from the lack of any kind of testing for safety, or its suppression if done.
Now, take a look at what started all this. Advertizements like these:
The firm named, National Lead Company, started in 1772, per a collection of business documents at Harvard, and is still around as NL Industries.
Per Brands’ recent biography of the man, Ben Franklin evidently determined that lead was poisonous back in his day.