"What poison is to the average human being, Green Kryptonite is to Superman! Indeed, the only thing the Man of Steel has to fear in the entire universe is the ghastly green substance which was flung into space when the planet Krypton exploded!" (Act No. 291/1, Aug 1962: "The New Superman!")
When the planet Krypton exploded into fragments as the result of a cataclysmic chain reaction originating at the planet's core, all of Krypton's atomic elements "fused to become one deadly compound," a compound later to become known as kryptonite (S No. 61/3, Nov/Dec 1949: 'Superman Returns to Krypton!"). Sent hurtling into outer space by the force of the cataclysm, these "dazzling particles" of the demolished planet, all "laden with cosmic energy," were scattered throughout the far reaches of the universe in the form of meteors and meteoric fragments, emitting a deadly radiation to which only Kryptonian survivors are vulnerable (Act No. 141, Feb 1950: "Luthor's Secret Weapon"), "When a radioactive chain reaction exploded my native planet Krypton, long ago," notes Superman in August 1960, "chunks of Green Kryptonite were formed! They scattered throughout space as meteors Their peculiar radioactive rays can bring kryptonite-fever and death to any person from Krypton...but are harmless to Earth people!" (S No. 139/3: "The Untold Story of Red Kryptonite!").
In the texts, Green Kryptonite is referred to as "the strange element given off by the explosion of the planet Krypton" (Act No. 141, Feb 1950: "Luthor's Secret Weapon"); "the deadly rock-like element from the exploded planet Krypton whose radiations can paralyze Superman" (Act No. 142, Mar 1950: "The Conquest of Superman!"); "the one substance.., that can overpower the Man of Steel" (Act No. 152, Jan 1951: "The Sleep That Lasted 1000 Years"); "the rare element, whose mysterious radiation is the only known force capable of overcoming Superman" (WF No. 50, Feb/Mar 1951: "Superman Super-Wrecker"); "a baleful new element whose rays affect only natives of Krypton" (Act No. 158, Jul 1951: "The Kid from Krypton!"); "the meteor metal caused by the explosion of Superman's native planet" (WF No. 56, Jan/Feb 1952: "The Superman Pageant!"); "the rare element from the shattered planet Krypton whose radiations have a deadly effect on Superman" (Act No. 174, Nov 1952: "The Man Who Shackled Superman!"); the "one element in all the universe can overcome" Superman (Act No. 181, Jun 1953: "The New Superman"); "the one substance that can destroy" Superman (Act No. 235, Dec 1957: "The Super-Prisoner of Amazon Island"); "the one substance in the universe feared by Superman" (Act No, 236, Jan 1958: "Superman's New Uniform!") and "Superman's one fatal flaw" (S No. 136/2, Apr 1960: "The Secret of Kryptonite!").
In the words of Superman No. 84/2 -- "Kryptonite, the radioactive particles of the former planet Krypton on which Superman was born, and which later exploded, is the one substance in the universe that can affect the mighty Man of Steel! Since kryptonite fragments still float in space after the explosion of the planet, some particles often find their way to Earth embedded in meteors" [Sep/Oct 1953: "A Doghouse for Superman!"].
"Bullets! ... Fire! ... Bombs!... Acid! I'm immune to them all!" muses Superman ruefully in July 1959. "But kryptonite is my Achilles heel ... the only substance in the universe that can harm me! It was originally formed years ago...when the planet Krypton, the world on which I was born, blew up! A nuclear chain-reaction converted every chunk of the exploding world into glowing green kryptonite!" (S No. 130/1: "The Curse of Kryptonite!").
More recent texts assert that the entire planet Krypton and every single thing on it was transformed into Kryptonite by the force of the cataclysm (Act No. 314/1, Jul 1964: "The Day Superman Became the Flash!"; and many others). Numerous earlier texts, however, maintain that whereas the planet itself was transformed into Kryptonite, its buildings and other artifacts of civilization were not (S No. 74/1, Jan/Feb 1952: "The Lost Secrets of Krypton!"; and many others).
Green Kryptonite is a radioactive (S No. 89/3, May 1954: "One Hour to Doom!") metal (WF No. 56, Jan/Feb 1952: "The Superman Pageant!") which is characterized by a distinctive "greenish glow" (Act No. 235, Dec 1957: "The Super-Prisoner of Amazon Island"; and others) and "has certain properties similar to radium" (Act No. 167, Apr 1952: "The Machines of Crime!"). Colored red in its initial textual appearance (S No. 61/3, Nov/Dec 1949: "Superman Returns to Krypton!"), Green Kryptonite has been colored green in every text since then. Although Action Comics No. 158 states flatly that "No substance will screen kryptonite's rays...not even Supermanium" (Jul 1951: "The Kid from Krypton!"), innumerable texts have maintained since then that Green Kryptonite radiations are unable to penetrate lead (S No. 92/3, Sep 1954: "Superman's Last Hour!"; and many others). It is interesting that though Superman may not be able to resist the effects of Green Kryptonite, or make himself generally immune to it as a substance, one account tells of Superboy gathering very specific pieces of Green Kryptonite so that he gains immunity to at least those particular chunk's deadliest effects -- in this case so he might use them to later battle Kryptonian criminals exiled in space before the Phantom Zone was used (SB No. 58/3, Jul 1957: "The Great Kryptonite Mystery").
In March-April 1954, Superman neutralizes the radioactivity of a Green Kryptonite meteor merely by plunging it into the ocean (WF No. 69: "Jor-El's Last Will!"), but the notion that the baleful effects of Kryptonite can be neutralized by seawater is contradicted by numerous other texts: "Ah! My X-ray vision shows a kryptonite meteor that fell to the sea bottom!" muses Superman in December 1958. "But to pick it up, I'll need the protection of lead, which alone can stop the deadly radiations!" (Act No. 247: "Superman's Lost Parents!"; and many others).
According to Action Comics No. 158, powerful acids and even man-made lightning cannot destroy Green Kryptonite (Jul 1951: "The Kid from Krypton!"), but Superman has successfully melted the substance with his X-ray vision (Act No. 252/1, May 1959: "The Menace of Metallo!"; and others) and Green Kryptonite meteors dissolve completely when subjected to the searing heat at the core of the sun (WF No. 61, Nov/Dec 1952: "Superman's Blackout"; see also Act No. 161, Oct 1951: "Exitâ€”Superman!"). The reason Green Kryptonite meteors do not burn up from air friction when they enter Earth's atmosphere is that "kryptonite can't combine chemically with oxygen, which causes combustion!" (S No. 130/1, Jul 1959: "The Curse of Kryptonite!"; see also Act No. 267/1, Aug 1960: "Hercules in the 20th Century!").
Assuming that the necessary advanced technology were available to utilize it, Green Kryptonite could become an invaluable source of atomic power. It retains its radioactivity "for centuries" (Act No. 161, Oct 1951: "Exitâ€”Superman!") and is described as a more potent power source than uranium (Act No. 252/1, May 1959: "The Menace of Metallo!"). Its principal drawback appears to be that it "crumbles and destroys any generator" in which it is utilized (Act No. 224, Jan 1957: "The Secret of Superman Island!"), but this has not prevented at least one group of extraterrestrial aliens from developing a powerful "rocket fuel composed of liquid green kryptonite" (Act No. 296/1, Jan 1963: "The Invasion of the Super-Ants!"). Green Kryptonite also has properties that nourish the development of certain forms of plant life (Act No. 169, Jun 1952: "Caveman Clark Kent!"). It also proves to be a key ingredient in the formula devised by Brainiac 5 for a serum that helps Mon-El survive exposure to lead (Adv No. 316/2, Jan 1964: "Origins and Powers of the Legion of Super-Heroes!").
In January 1971, Professor Bolder attempts to harness a "super chain-reaction" in Kryptonite in order to to generate electrical power. He fails and the uncontrolled feedback changes much of the Green Kryptonite on Earth to iron (S No. 233/1: "Superman Breaks Loose"). However, Synthetic Kryptonite and the many fragments of the material still in space remain.
Although numerous texts describe Green Kryptonite as an exceedingly rare substance (Act No. 181, Jun 1953: "The New Superman"; and many others), noting that â€œkryptonite meteors that [fall] on Earth are rareâ€ (Act No. 238, Mar 1958: "The Super-Gorilla from Krypton"), other texts, admittedly fewer in number, maintain that "kryptonite meteors often fall from space" (S No. 134, Jan 1960: chs. I-IIIâ€”"The Super-Menace of Metropolis!"; "The Revenge Against Jor-El!"; "The Duel of the Supermen!") and that "particles [of kryptonite] often find their way to Earth embedded in meteors!" (S No. 84/2, Sep/Oct 1953: "A Doghouse for Superman!"). On balance, however, the evidence of the texts is that Green Kryptonite is "very rare" and not easily acquired (S No. 128/1, Apr 1959: chs. I-IIâ€”"Superman versus the Futuremen"; "The Secret of the Futuremen"; and others).
It is presumably the relative scarcity of Green Kryptonite, combined with its crushingly debilitating effect on Superman, that has motivated a number of villains to find ways to synthesize it. Lex Luthor creates the first synthetic Kryptonite (Green) in February 1950 by ingeniously fusing together "a mammoth pearl from one of the giant oysters miles down under the sea"; "a couple of handfuls of dust from the dark side of the moonâ€; "pollen from the man-eating homocessandi plant deep in the Asiatic jungles"; and "a bit of the rare chemical binarium, preserved in the soil by a thousand years of glacial frost" (Act No. 141: "Luthor's Secret Weapon").
Dr. Vallin devises a formula for synthesizing Green Kryptonite in January-February 1952 that calls for stockpiling gold, silver, lead, and bismuth and then "fusing the...ore with acid and crackling electricity" (WF No. 56: "The Superman Pageant!").
A third method of synthesizing Kryptonite, successfully employed by Lex Luthor in August 1953, is based on Luthor's observation that:
Each piece of metal that strikes Superman's invulnerable body undergoes a slight chemical change! To a minute degree, it acquires the properties of kryptonite, but its presence is so faint that it can only be detected by means of a spectroscope!
Kryptonite is the one material that can harm Superman! By refining tons of this metal, I'll be able to extract kryptonite---just as radium is obtained by refining tons of uranium ore! [Act No. 183: "The Perfect Plot to Kill Superman!"].
In addition, a Green Lantern's power ring can create Green Kryptonite, but maintaining its existence and its radioactivity requires concentration by the ring's wielder (DCCP No. 26, Oct 1980: "Between Friend and Foe!").
Whether the Kryptonite is natural or synthetic, however, its effects on Superman are devastating, although they do vary according to the amount of kryptonite involved and Superman's distance from it. Large meteors produce the worst effects, but close proximity to even a small quantity of Green Kryptonite, such as a piece the size of a large decorative gem, is sufficient to make Superman feel "like a feeble old man," incapable of even touching the kryptonite without losing consciousness (S No. 61/3, Nov/Dec 1949: "Superman Returns to Krypton!").
"As soon as I approach kryptonite," observes Superman in April 1952, "I become weak!" (Act No. 167: "The Machines of Crime!"). Other texts refer to such symptoms as "dizzy spells," exhaustion, and grogginess (Act No. 169, Jun 1952: "Caveman Clark Kent!"; and many others); nausea (S No. 81/2, Mar/Apr 1953: "20,000 Leagues Under the Sea with Superman"); loss of consciousness (S No. 66/2, Sep/Oct 1950: "The Last Days of Superman!"; and many others); and temporary impairment—or even complete loss—of memory (S No. 71/1, Jul/Aug 1951: "Clark Kent's Super-Masquerade!"; and others). Typically, Superman's pupils become dilated, his pulse rate falls below normal, and his respiratory rate is reduced by half (S No. 66/2, Sep/Oct 1950: "The Last Days of Superman!").
If lured to within close proximity of a fairly large chunk of Green Kryptonite, such as a meteoric fragment about the size of a basketball, Superman suffers a nearly total loss of his super-strength accompanied by an agonizing semi-paralysis, referred to in the texts as a "kryptonite paralysis" (Act No. 218, Jul 1956: "The Super-Ape from Krypton"; and others) and the drastic diminution of all his super-powers.
For the effects of Kryptonite to prove fatal may take hours (S No. 92/3, Sep 1954: "Superman's Last Hour!"; and others) or even days, but gradually, under "constant exposure" to the kryptonite radiations, Supermanâ€™s "mighty body becomes emaciated and his keen mind grows dim..." (S No. 77/2, Jul/Aug 1952: "The Greatest Pitcher in the World!"; and others).
As the last vestiges of his mighty powers begin slowly waning, Superman "begins to feel pain from the steady exposure to the kryptonite," and he lapses into a potentially fatal "kryptonite fever," similar in many respects to that which afflicts ordinary people who have been "over-exposed to radium rays!" Even if drugs were available to treat the illness, they could not be injected, for "the hypodermic needles [would] only bend" against Superman's invulnerable skin.
"The kryptonite radiations will soon penetrate my otherwise invulnerable skin and change the red corpuscles of my bloodstream to green!" thinks Superman desperately in July 1959 as he suffers the agonizing effects of exposure to a Green Kryptonite meteor. "I'll become a victim of blood-poisoning!" (S No. 130/1: "The Curse of Kryptonite!").
Indeed, if Superman were not rescued from the baleful radiations in time, his body would begin to exude a greenish glow, like that of the deadly Kryptonite itself, and he would lapse into a coma and die. Superman has never succumbed to this terrible fate, but other Kryptonian survivors have, including King Krypton (Act No. 238, Mar 1958: "The Super-Gorilla from Krypton") and virtually all the inhabitants of Argo City (Act No. 252/2, May 1959: "The Supergirl from Krypton!").
Superman has, however, amazing recuperative powers. Although, on a number of occasions, he has remained physically weak for a short time after having suffered the effects of Kryptonite exposure (S No. 66/2, Sep/Oct 1950: "The Last Days of Superman!"; and others), in the vast majority of cases he recovers his full powers within moments after the debilitating Kryptonite has been removed from his presence (Act No. 141, Feb 1950: "Luthor's Secret Weapon"; and many others).
The texts are divided, however, on the question of whether Green Kryptonite radiations are capable of weakening Superman to the point of robbing of him of his invulnerability—thereby rendering him vulnerable to guns, bombs, and other ordinary weapons (WF No. 87, Mar/Apr 1957: "The Reversed Heroes!"; and others), or whether, as most texts dealing with this question contend, Superman retains his invulnerability despite prolonged exposure to kryptonite and can only be killed by the Kryptonite itself (Act No. 299/1, Apr 1963: "The Story of Superman's Experimental Robots!"; and many others).
In situations in which Superman has no superpowers, such as that which exists in October 1964, after the Man of Steel has been stripped of his powers by the baleful radiations of a mysterious green comet, he becomes immune to Green Kryptonite radiations until such time as his super-powers have been restored to him (S No. 172: pts. I-IIIâ€”"The New Superman!"; "Clark Kentâ€”Former Superman!"; "The Struggle of the Two Supermen!"; and others).
Once having been lured into a Kryptonite deathtrap, Superman has coped with the deadly substance in a variety of ways, such as by using his waning X-ray vision to melt an object containing lead around the kryptonite, thereby shielding himself from its radiations (S No. 145/1, May 1961: "The Secret Identity of Superman!"), or by burning a hole in the floor with his weakened X-ray vision in order to make the kryptonite fall safely out of life-threatening range (S No. 77/2, Jul/Aug 1952: "The Greatest Pitcher in the World!"). On one occasion, Superman successfully wards off the agonizing pain induced by Green Kryptonite exposure—albeit only for a few crucial moments—by literally hypnotizing himself into not feeling the pain (Act No. 278/1, Jul 1961: "The Super Powers of Perry White!").
Superman has had some success with melting small chunks of Kryptonite with his X-ray vision (Act No. 252/1, May 1959: "The Menace of Metallo!"), but this technique is inadequate for dealing with larger masses of the substance, such as, for example, an entire Kryptonite meteor or meteorite (Act No. 254/1, Jul 1959: "The Battle with Bizarro!"; S No. 130/1, Jul 1959: "The Curse of Kryptonite!").
Because Green Kryptonite is the bane of his existence, Superman has conducted numerous experiments in search of an antidote, but all his efforts have ended in failure (Act No. 158, Jul 1951: "The Kid from Krypton!"; and others). He has also experimented with building up an immunity to the substance through controlled exposure to it, but these attempts, too, have been unsuccessful (S No. 84/2, Sep/Oct 1953: "A Doghouse for Superman!"). Superman has, however, successfully devised a suit of special lead armor to enable him to experiment with the substance (Act No. 241, Jun 1958: "The Super-Key to Fort Superman"; Act No. 249, Feb 1959: "The Kryptonite Man!") as well as a special "kryptonite detector" (Act No. 243, Aug 1958: "The Lady and the Lion"), also referred to as a "K-detector", which "detects kryptonite as a Geiger counter does uranium" (Act No. 158, Jul 1951: "The Kid from Krypton!").
For handling Green Kryptonite without his special lead armor, Superman has employed remote-controlled robots (Act No. 158, Jul 1951: "The Kid from Krypton!"), gigantic shovels (S No. 71, Jul/Aug 1951: "Clark Kent's Super-Masquerade!") and tongs (S No. 113, May 1957: chs. 1-3â€”"The Superman of the Past"; "The Secret of the Towers"; "The Superman of the Present"; and others), and other special tools (S No. 115/2, Aug 1957: "Jimmy Olsen's Lost Pal"; and others) designed to enable him to handle, or dispose of, the Kryptonite without venturing too close to it. According to Superman No. 130/1, Superman remains safe from harm as long as he remains "at least 100 feet from the radiations ..." (Jul 1959: "The Curse of Kryptonite!").
In April 1958, Superman finds the secret of his dual identity in jeopardy after a bizarre series of circumstances, culminating in the explosion of an experimental atomic generator, has cause tiny fragments of Kryptonite to become embedded in his forehead, spelling out the name of Clark Kent.
For a time Superman is compelled to hide his face, first with cloth bandages and later with a metal mask, to avoid people seeing it and learning his secret. Ultimately, he succeeds in burning the Kryptonite particles out of his skin by deliberately exposing himself to an awesome atomic explosion in space, described by the text as "the mightiest atomic explosion of all time" (Act No. 239: "Superman's New Face!").