In April 1917, the United States entered World War I, and a massive industrial demand immediately arose for a product that had existed only as a scientific curiosity: paint that glowed in the dark. Powered by the radioactive decay of radium, this toxic paint has a special prominence in the history of workplace safety regulation and workers’ compensation law in the United States. The radium paint episode lies at the nexus of competing American traditions of corporate greed and progressive social justice. It is a cautionary, Promethian tale of commercial technological advances outpacing deliberate exploration of the relevant hazards. Its lessons underlie the modern practice of workplace radiation safety central to my career as a nuclear engineer. In this post commemorating 100 years of the American radium paint industry, I will illustrate some of the landscapes associated with the nascent radium industry of a century ago, taken with my own camera (and there are historical photos thrown in for then-and-now comparisons).
Let’s begin with an historical image, showing Ukrainian immigrant inventor Sabin Arnold Sochocky sitting casually next to one gram of radium bromide. That is one Curie of activity in the little evaporating dish, a massive uncontained radiation source by today’s standards. (Aside: for anyone who might perchance have to choke on this man’s name in D. W. Gregory’s well-known “Radium Girls” stage play: it is transliterated from Сохоцький, pronounced “Sokhotsky”.) Sochocky invented a stable and brightly-luminous paint formula using radium, and in 1917, his company—then called Radium Luminous Material Corporation—started mining the remote carnotite deposits of Paradox Valley, Colorado for radium. Simultaneously, Sochocky built a plant to process the ore, extract radium, make paint, and apply the paint to dials at the corner of Alden and High Streets in Orange, New Jersey. He branded his paint “Undark”. Although there would eventually be many competitors in the radium business, Sochocky was first out of the gate. He promised that “The time will doubtless come when you have in your own home [...] a room lighted entirely by radium.” (You’re probably sitting in your radium room while you read this, right?)
Radium is a product of the radioactive decay of uranium, and accompanies it in nature. In the early 20th century, known deposits of radium and uranium were few. One of the epicenters of early American radium mining was along the walls of Paradox Valley, Colorado—an incredibly remote collapsed salt anticline in the canyon country of the state’s far southwest. Uranium concentrated in fronts of organic debris trapped in the alluvium of the Jurassic coastline, and surfaced in exposures of these sandstone strata as bright-yellow carnotite (example shown below). The Radium Luminous Materials Corporation established very productive mines on the north wall of Paradox Valley, such as the Cripple Creek Mine (pictured below), during 1917-1920. It would be joined by several other competing companies in the region. Miners lived in primitive camps. Their work involved heavy manual labor, explosives, and exposure to radon gas, then poorly understood. However, this was high-paying work in order to entice men to the remote camps. Burro trains hauled hand-graded, burlap-sacked carnotite ore to distant railheads, and thence it would be carried back by train to Orange, NJ for processing.
Ore mined by Sochocky’s company traveled to Orange, New Jersey, to a repurposed steel works with a rail spur and plenty of water supplied by Wigwam Brook at the corner of High and Alden Streets. A fantastic summary of the technical processes at the Orange site is provided here. The ore was contacted with hydrochloric acid to leach the metal values, leaving behind silicate tailings that went on to be problematically used as building fill in the neighborhood. Radium was purified from barium by laborious fractional crystallization as the bromide. This messy job was done in the single-story structure shown in the two photos below. In this crystallization laboratory, workers toiled without respiratory protection in a radon-saturated atmosphere, leaning over unshielded, visibly-glowing, open dishes of radium and barium bromide salt solutions containing massive radioactivity. Sochocky himself often handled the refined product with his bare hands when he used an electroscope to quantify the activity, and was known to be so personally radioactive that corrections had to be applied to activity measurements he made. The Crystallization Laboratory was demolished in the 1990s during site cleanup.
To make “Undark” paint from purified radium according to Sochocky’s recipe, the radium was reprecipitated as a sulfate and then mixed with a proprietary zinc sulfide phosphor powder “doped” with certain trace elements (silver, copper, and manganese). This powder was stirred with solvents and a gum base to form paint. Workers, paid by the piece, applied the paint to dials and other articles with fine brushes. They were mostly women in their teens and twenties. Company protocol instructed them to “tip” the brushes in their mouths, thus exposing them to massive internal radium contamination.
In 1921, under financial pressure from cheap Belgian radium mined at Shinkolobwe, the directors of RLMC ousted Sochocky and replaced him with the treasurer, an aspiring young salesman from Cornell named Arthur Roeder. The company was renamed United States Radium Corporation. The next three years revealed a serious problem: dial painters and other plant workers (including Sochocky himself) were becoming ill with debilitating bone maladies at an alarming rate. The new president would inexpertly navigate the company’s mounting workplace health crisis as he chased profits, ultimately alienating the public, the workers, hired consultants, local health authorities, and even the company’s founder. At first, Roeder ignored evidence of a workplace-related cause for the illnesses. Later, as women in the Paint Application Building began dying, he defrauded county health authorities by forging parts of a consultant industrial hygienist’s report on radium safety, and stubbornly refused to be transparent about the full extent of what he knew. (Think Exxon and global warming, or tobacco companies and lung cancer.) Toxicologist Alice Hamilton exposed Roeder’s fraud in 1925 by appealing to the consultant hygienist’s wife, who had the original report released. With Roeder unmasked as a villain in the public eye, the radium industry was revolutionized by new regulatory oversight. The right of workers to sue employers for unsafe working conditions leading to provable harm was cemented into law. The power and purpose of responsive public health authorities, labor advocacy organizations, and diligent journalism were demonstrated to great effect.
Radium paint did not cease to be manufactured in 1928 when US Radium settled the “Radium Girls” lawsuit. In fact, it remained in use as a luminous material through the 1960s, albeit with enhanced safety measures that eliminated “radium jaw” as an occupational disease. US Radium also survived the episode, though not in Orange, NJ, where it closed its plant. Sabin Arnold Sochocky died in 1928 of aplastic anemia, the same radium-related disease that ultimately killed Marie Curie. The “Radium Girls” party to the lawsuit all died over the next five years. Most of the mines in Paradox Valley would be closed down, only to be reworked for uranium once that element took on new importance during WWII.
The story of radium paint as an industrial commodity turns 100 this month. Thus it is fitting to reflect on it as a uniquely American story of corporate profits and human responsibility, of technological fads and scientific understanding, and of the roles of government, journalists, and labor rights activists in promoting a more just social contract. The perspective I add is that of a technically-interested nuclear engineer who has visited these sites, radiation detector in hand, hunting for the telltale “click” of unstable nuclei attesting to the living past. Radiation-impacted sites are often neglected and walled off, but can be historically important and worthy of our pilgrimage and respect. There are numerous other perspectives on the radium paint episode that I am ill-equipped to treat. With this in mind, I welcome comments and messages, suggestions and corrections. Thanks for your interest!