In the early 1900s, according to coffee lore, German coffee merchant Ludwig Roselius discovered decaf by accident after a shipment of coffee beans was soaked in seawater during transit, naturally extracting some of the caffeine.
A few years later, Roselius patented the first commercially successful means of decaffeinating coffee. But instead of just salt water, his method also used a more potent chemical solvent called benzene to finish the job.
We now know that when inhaled, even in small amounts, benzene can cause drowsiness, dizziness, and headaches, as well as eye, skin, and respiratory tract irritation. Over the long term and in high doses, benzene has been linked to cancer, blood disorders, and fetal development issues in pregnant women.