Many people know the tragic story of the “radium girls,” the luminous-dial painters of the flapper era who tipped their paintbrushes in their mouths, became sickened from internal radiation exposure, and had to fight for workers’ compensation as they died. Although a large number of radium paint factories existed, one in particular is identified with this infamous episode: the United States Radium Corporation, sited on two acres at the southwest corner of High and Alden Streets in Orange, New Jersey. This factory was built in 1917 for the combined purposes of radium extraction, purification, and paint application. Two original buildings—including the paint application building—remained standing until the US EPA had them torn down as part of a Superfund remediation project in 1998. Today, the site is a barren, fenced-in, field with no hint of radioactivity betraying its former capacity. In this post I’ll share a few photos from my trip this month, from the Library of Congress’s archive of the recent past, and even one from the plant’s heyday. I’ll share some quotes about the technical operation of this facility, and a pic of my samples of its product, Undark.
The former U.S. Radium site viewed from the southeast corner in 2012. A railroad track once paralleling the confined Wigwam Brook brought 100-lb sacks of carnotite from Paradox Valley, CO, as well as soda ash, to a siding here. Radium was extracted in a long-since-demolished building at this corner of the property before going to the crystallization lab and ultimately the paint shop on site. Hydrochloric acid, the main extractive lixiviant, was stored in a tank on the opposite side of the property.
Paint Application Building, exterior: About 300 dial painters, virtually all of them young women, came to work here between the years of 1917 and 1926.
South-easterly view of U.S. Radium’s paint application building from Alden Street, mid-1990s (public-domain photo from the Library of Congress). Grace Fryer and her dial-painting cohort probably ingested their fatal doses of radium on the second floor of this building.
A similar view today (2012): all that’s here now is an empty field behind a fence. A scintillation counter measures nothing above background levels of gamma radiation.
Paint Application Building, interior: “Dial painting areas had four parallel rows of work benches, aligned with the building’s longer axis. Both floors included large wooden, double-hung, triple windows, and at least one section of the upper floor appears to have skylights.”
Second floor of the Paint Application Building, interior view to the southeast in this 1922 photo belonging to Argonne National Laboratory. Note the open skylights.
The same room, late 1990s, Library of Congress photo. The skylights have been filled in, but their recesses and original plumbing are still visible. The floor has been replaced.
Crystallization Laboratory: From the element’s discovery well into the 1950s, the only practical chemical technique for separating radium from barium was arduous multi-stage fractional crystallization. U.S. Radium used a chloride and bromide system, as described by Florence Wall, plant chemist: “…in the crystallization laboratory, large quantities of radium chloride solution from the plant progressed in stages from silica tubs, three feet in diameter and about a foot deep, into smaller evaporating dishes until, after conversion, the product appeared as a few crystals of radium bromide in a tiny dish, 1/2 inch in diameter.”
The one-story crystallization lab as it looked from the northwest, in this mid-1990s Library of Congress photo. Behind it is the Paint Application Building.
In 2012, the grass covers all. (The same house can be seen in the background in both images.)
The Product: U.S. Radium named its radioluminous paint Undark. An article that was painted with this product was said to be “Undarked.” The formula of Undark varied with application and was a trade secret. At the time of the “Radium Girls” poisoning, a single employee named Isabel manufactured a zinc sulfide base activated with trace quantities of cadmium, copper, and manganese. Another employee, originally company founder S. A. von Sochocky, added a measured amount of radium to the base and fixed it in its insoluble sulfate form: “[D]epending upon the type of work the material is to be used for the element of radium varied from one part of radium element to 140,000 parts of the base—zinc sulphide, to one part of radium element to 53,000 parts of the base [about 20 microcuries per gram]. The radium element when added to the zinc sulphide […] is in an aqua solution. When that is added to the zinc sulfide which is in the form of a dry powder, it becomes like a paste. The radium element when mixed with the sulphide powder is soluble. In order to make certain that it will become insoluble and also that it will be equally distributed in the paste and also to prevent the radium element from being dissolved later when water is applied to it, I converted the radium into radium sulphate which is insoluble by adding amount of ammonium sulphate also in an aqua solution.”
Undark, dated 1940, made to Army Specification 3-99D, packaged in 1g vials. Each produces a gamma exposure rate of about 40 mR / hour on contact, broadly consistent with about 20 microcuries of Ra-226 activity per gram.
The Waste: Anything that was not radium—i.e. the vast majority of the ore that entered the plant—was waste and had to find a new home! This included the uranium content of the ore; preceding the discovery of fission, uranium was effectively worthless. One common application for U.S. Radium tailings was infill for construction projects in nearby Glen Ridge, Montclair, and Orange. Contaminated fill was identified, dug up, and replaced throughout the 1990s.
Carteret Park (e.g. Barrows Field), located in Glen Ridge, was originally filled with waste tailings from U.S. Radium. Third base was rumored to be particularly “hot.” The entire ballfield was dug up, trucked away in drums, and restored with clean fill in 1998.
The hottest spots at Barrows Field today are along the concrete fence wall. Whether the minor detected radioactivity is owing to natural occurrence in the concrete materials, or un-remediated residues from U.S. Radium, is impossible to say.
Historic American Engineering Record HAER NJ-121, National Park Service (1996) (All quotations in italics above are from this source.)
Photographs from above record by Thomas R. Flagg, Gerald Weinstein, 1995-1996, at the U.S. Library of Congress