Lead

Lead

A fairly common metal found on Earth and possessing qualities of extreme density and softness. Lead is toxic to humans in small amounts and its use is now more restricted, but it remains valuable for screening radiation and is still important in many industrial metal alloys and some paints.

Perhaps no metal on Earth is as important in Superman's career as lead. It protects him from the harmful radiation of Kryptonite, but at the same time, blocks all of his extra vision powers, including being resistant to heat vision.

Lead is extremely harmful to Daxamites, weakening them and shortening thir lives (SB No. 89, Jun 1961: "Superboy's Big Brother!"; "The Secret of Mon-El!"). As a result, Mon-El moves to the Phantom Zone until a temporary remedy devised by Saturn Girl enables him to join the Legion of Super-Heroes (Adv No. 300, Sep 1962: "The Face Behind the Lead Mask!"). Later, Brainiac 5 devises an improvement, and makes a serum that Mon-El takes every 48 hours and gives him more permanent protection against lead (Adv No. 316, Jan 1964: "Origins and Powers of the Legion of Super-Heroes!").

Both the Anti-Superman and Anti-Batman use lead-lined masks to prevent Superman from discovering their real identities with his X-ray vision (WF No. 159/1, Aug 1966: "The Cape and Cowl Crooks!").

Lex Luthor has created laboratory hideouts that has been lined with lead to conceal them from Superman's X-ray vision, see Luthor's Lair, Luthor's Lair II, and Luthor's Lair No. 5.