1 There went our best chance: In the ninth century, a team of Chinese alchemists trying to synthesize an "elixir of immortality" from saltpeter, sulfur, realgar, and dried honey instead invented gunpowder.
2 German scientist Hennig Brand stored 50 buckets of urine in his cellar for months in 1675, hoping that it would turn into gold. Instead, an obscure mix of alchemy and chemistry yielded a waxy, glowing goo that spontaneously burst into flame—the element now known as phosphorus.
3 Soldiers supplied the raw material in vast, sloshing quantities until the 1750s, when Swedish chemist Carl Scheele developed an industrial method of producing phosphorus. He discovered eight other elements, including chlorine, oxygen, and nitrogen, and compounds like ammonia, glycerin, and prussic acid.
4 Scheele was found dead in his lab at age 43, perhaps owing to his propensity for tasting his own toxic chemicals.
5 Kevlar, superglue, cellophane, Post-it notes, photographs, and the phonograph: They all emerged from laboratory blunders.
6 The Flash, created in 1940 for All-American Publications, was the first comic book hero to develop superpowers after a lab accident, attaining "super speed" after inhaling "hard water" vapors.
7 Other beneficiaries of the Freak Lab Mishap include Plastic Man (struck by a falling drum full of acid), the Hulk (irradiated by an experimental bomb), and of course, Spider-Man (bitten by a radioactive spider).
8 In real life, perhaps a bigger risk comes from lab-contracted diseases. The world's last documented case of smallpox killed photographer Janet Parker in 1978 after the virus escaped from a lab at the University of Birmingham in England.
9 But sometimes humans strike back: Alexander Fleming, famous for his serendipitous discovery of penicillin, also chanced upon an antibiotic enzyme in nasal mucus when he sneezed onto a bacterial sample and noticed that his snot kept the microbes in check.
10 The lab-accident rate in schools and colleges is 100 to 1,000 times greater than at firms like Dow or DuPont.
11 In 1938 DuPont chemist Roy Plunkett opened a dud canister of tetrafluoroethylene gas and discovered an amazing, nearly friction-free white powder. He named it Teflon.
12 Perhaps he should have chucked it out instead: In 2005 the Environmental Protection Agency identified a Teflon ingredient, perfluorooctanoic acid, as a "likely carcinogen." It is now in the bloodstream of 95 percent of Americans.
13 After a 1992 drug trial in the Welsh mining town of Merthyr Tydfil, male subjects reported that sildenafil citrate hadn't done much for their angina, but it did have an unusual side effect on another part of their anatomy. Today the drug is sold as Viagra.
14 In 1943 Swiss chemist Albert Hoffman inadvertently absorbed a small quantity of lysergic acid through his fingertips and experienced "dizziness . . . visual distortions . . . [a] desire to laugh." The age of LSD had begun.
15 Hoffman's long, strange trip continues. He turned 100 this past January.
16 Why he's not the father of the electric chair: While trying to electrocute a turkey, Benjamin Franklin sent a whopping jolt from two Leyden jars into his own body. "The flash was very great and the crack as loud as a Pistol," he wrote, describing the incident as an "Experiment in Electricity that I desire never to repeat."
17 In 1965 astronomers Arno Penzias and Robert Wilson scrubbed their Bell Labs radio antenna to rid it of pigeon droppings, which they suspected were causing the instrument's annoying steady hiss.
18 That noise turned out to be the microwave echo of the Big Bang.
19 The world has scores of superpowerful particle accelerators. Last year, a fireball created at the Relativistic Heavy Ion Collider in Upton, New York, had the characteristics of a black hole. Physicists are reasonably sure that no such black holes could escape and consume Earth.