Lead

Lead is a metal. It is a pure element, and one of the heaviest metals. It is useful for its density in fishing tackle, shipping, and artillery projectiles. Lead is malleable and has good corrosion resistance. In gasoline it raises the octane, and in paint it makes the paint smooth, opaque, and long lasting.

In ancient Rome, lead was used extensively in water supplies. The latin name, Plumbum, lead to the words plumbing and plumber.

In the late 20th century it was discovered that chronic lead exposure is neurotoxic, and it was removed from gasoline, paint, plumbing, and drinking vessels.

It was also removed from most solder used for electronics, but military and hospital uses are exempted because lead solder is still the best available for reliability.