Lead, arsenic, uranium, and other toxic elements were once used in pigments for producing vibrant colors.

Lead was one of the earliest metals mined on Earth, desired for its soft malleability and used in cosmetics, pipework, gasoline, and more. But even though researchers demonstrated its toxicity in the 20th century, much of the world still uses it.

In 1856, a chemist accidentally discovered mauveine, the world's first synthetic dye, while trying to make quinine to treat malaria. The synthetic dyes that followed helped reveal germs under microscopes, paving the way for modern imaging techniques and breakthrough treatments, such as antibiotics.

After radium was discovered in 1898, companies began using radium-based paints on watch and clock dials to create a glow-in-the-dark effect. Women who worked to apply the paint were encouraged to use their lips and tongues to help create the fine point needed to draw small numbers, unknowingly poisoning themselves.

Titanium white can be found in items ranging from paint to pills. Though it was created in New York in 1908, the pigment was first used hundreds of years earlier by the Inca, according to this article.

The red light originates from a long-lasting excited electron state in the element's atomic structure. The brittle gray metal has historically been used in pigment production, the manufacturing of rust-resistant stainless steel, and the creation of durable coatings with long-lasting shine for metals, wood, and leather.

In 1896, Henri Becquerel had been exploring phosphorescence—the emission of light of one color after an object is exposed to another color. He expected these emissions to come from objects exposed to sunlight, but he observed emissions after an overcast day.

Lignum nephriticum, a tea used to treat kidney and urinary illnesses, was described in the 16th century as derived from white wood that turned water a bluish hue. However, in the 17th century, accounts described the wood as reddish and creating a kaleidoscope of colors in water. In 1915, the sources were identified as two different woods, which absorb UV radiation and emit visible light.

Besides the various salts and metals used to produce fireworks colors, shells are also filled with gunpowder and oxidizers to help fuel and accelerate reactions. Chlorates help strengthen colors, while dextrin, a starch, helps hold mixtures together.

Uranium is commonly found in rocks, water, and soil worldwide, but significant industrial processes are needed to process and enrich it for efficient reactor usage. After being irradiated in reactors, it must be cooled down before disposal.

With hundreds of ink manufacturers, all unregulated by the FDA, it’s hard to determine the exact ingredients in tattoo inks. Some pigments may contain carcinogenic chemicals, such as heavy metals and aromatic hydrocarbons, or even bacterial contaminants. Red ink often causes allergic reactions and may even contain lead or mercury.

Those involved in the predecessor of the modern scientific discipline engaged in experimentation to develop recipes that would transform ordinary matter into gold and to create medicines, cosmetics, dyes, and alloys. Over the course of centuries, scientists identified unique elements, organized them based on their properties in the periodic table, and eventually developed the technology to discover the internal structure of atoms.

Consumer Reports' tests of more than 20 supplement powders and shakes in 2025 found that more than two-thirds of them contain unsafe levels of lead. Some contained 10 times the amount of lead that's considered acceptable to ingest in a day. The levels they found, in some cases, were even higher than when they tested the products 15 years earlier.

Rather than focusing solely on new mining operations, which can take decades to establish, some startups are developing methods to extract these metals from the toxic waste of existing operations and thereby minimize environmental impacts.

Although modern nonstick pans avoid forever chemicals like PFOA, they were previously used in the manufacturing of Teflon coatings and have been linked with certain types of cancer, infertility, and other adverse health outcomes. Vintage plastic utensils should also be avoided due to the leeching of contaminants in early formulations of plastic.

Many small-scale operations worldwide remain unregulated, bypassing environmental regulations and causing increasing health threats, primarily to children. A 2020 report by UNICEF found that one-third of the world's children are being poisoned by lead from recycled batteries, among other sources.

Most modern processed foods rely on a number of preservatives to stay fresh from production to our plates. The most common include citric acid (preservative and flavor), sodium benzoate (preservative), xanthan gum (thickening and stabilizing), carrageenan (thickening), and red dyes 3 and 4 (for color).

Ionizing radiation produced by elements such as uranium, polonium, and radium can damage living things, but the trace amounts found in the museum objects that Marie Curie once touched have been largely decontaminated, with more dangerous items stored in protective, lead-lined containers.

Archaeologists stumbling upon statues from ancient Greece often found weathered creatures, their faces and figures marred by age and conflict. But evidence of polychromy—painting sculptures with color—has continued to mount.

The extraction and processing of REEs requires significant amounts of water, and poorly regulated projects can contaminate groundwater with acids and heavy metals. Toxic waste spills have paused work in several US mines since the 1980s, despite growing REE demand.

Lead, arsenic, asbestos, and other chemicals have been found trapped in smoke-exposed rugs, couches, pillows, and other furniture that appeared otherwise undamaged from the 2025 LA wildfires. The gradual release of these substances has produced dangerous indoor air concentrations and contributed to increased emergency room visits and abnormal blood tests.

As part of government research, a group of young men were paid to eat standard American food—replete with food additives like borax and formaldehyde—which revealed the dangers of unregulated food. The work was led by the first FDA commissioner, Harvey Wiley, who helped end the "century of the great stomachache."

Solar panels use silver due to its high conductivity, hydropower plants use chromium in their steel alloys, and geothermal plants need titanium to withstand abundant heat and pressure. Lithium—used in energy storage—is expected to see over 500% increased demand from 2020 to 2025.

Their discoveries of polonium and radium involved ongoing exposure to radioactive materials before shielding technology was developed. Their notebooks, furniture, and other belongings remain radioactive today, requiring researchers to sign a waiver and wear protective clothing to access.