The town was noted for a fatal accident in 1966 in which a B-52 Stratofortress of the Strategic Air Command collided mid-air with a KC-135 Stratotanker plane, causing radioactive contamination after its payload of four hydrogen bombs (H-bombs) was dispersed and crashed.
The high-explosive igniters in two of these bombs detonated on impact, spreading radioactive material, including deadly plutonium-239, over a wide area of the Spanish countryside, but safety mechanisms and electronics prevented nuclear explosions.
The fourth H-bomb landed in the Mediterranean Sea, and U.S. Navy searchers took three months to find and recover the device intact.
In 2001, the Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT) still detected measurable levels of the radioactive elements plutonium, uranium, and americium over 10 hectares (24 acres) of Palomares.
[1] Annual monitoring by American and Spanish researchers founded no evidence of health problems, or of any contaminated food or water resulting from the accident.