The Radium Girls were female factory workers who contracted radiation poisoning from painting watch dials with self-luminous paint.
 Painting was done by women at three different sites in the United States, and the term now applies to the women working at the facilities.
 The first, United States Radium factory in Orange, New Jersey, beginning around 1917, at Ottawa, Illinois, beginning in the early 1920s, and a third facility in Waterbury, Connecticut.
Undark was a trade name for luminous paint made with a mixture of radioactive radium and zinc sulfide, as produced by the U.S. Radium Corporation between 1917 and 1938.
 It was used primarily in watch and clock dials.
 The people working in the industry who applied the radioactive paint became known as the Radium Girls, because many of them became ill and some died from exposure to the radiation emitted by the radium contained within the product.
 The product was the direct cause of Radium jaw in the dial painters.
 Undark was also available as a kit for general consumer use and marketed as glow-in-the-dark paint.
The Rock 'n' Roll Camp for Girls is both the original Rock n Roll Camp for Girls non-profit organization based in Portland, Oregon, United States, and the common name associated with the Girls Rock Camp movement of youth organizations for girls inspired by the original camp in Portland.
 The camp in Portland gives girls ages 8–18 the opportunity to learn rock instruments, form bands, write songs, and perform.
 The mostly volunteer and female staff strives to inspire self-esteem and mutual support among diverse campers within this rock band framework.
 The first camp was held in August 2001.
The Radium Dial Company, was one of a few now defunct United States companies along with the United States Radium Corporation, involved in the painting of clocks, watches and other instrument dials using radioluminescent paint containing radium.
 The resulting dials are now collectively known as radium dials.
 The luminous paint used on the dials contained a mixture of phosphorus and radium, a product that the Radium Dial Company named "Luna".
 However, unlike the US Radium Corporation, Radium Dial Company was specifically set up to only paint dials, no other radium processing took place at the premises.
Radium dials were almost always painted by young women, who used to 'point' their brushes by licking and shaping the bristles prior to painting the fine lines and numbers on the dials.
 This practice resulted in the ingestion of radium, which caused serious jaw-bone degeneration and malignancy and other dental diseases reminiscent of phossy jaw.
 The disease, radium-induced osteonecrosis, was recognized as an occupational disease in 1925 after a group of radium painters, known as the Radium Girls, from the United States Radium Corporation sued.
 By 1930, all dial painters stopped pointing their brushes by mouth.
 Stopping this practice drastically reduced the amount of radium ingested and therefore, the incidence of malignancy, to zero by 1950 among the workers who were studied.
The domestic international sales corporation is a provision unique to tax law in the United States.
 In 1971, the U.S. Congress voted to subsidize exports of U.S. made goods through the income tax law.
 The initial mechanism was through a Domestic International Sales Corporation (DISC), an entity with no substance which received tax benefits.
 Today, shareholders of a DISC continue to receive reduced income tax rates on qualifying income from exports of U.S. made goods.
Hall is a common surname of English origin.
 Hall means "kind" and "forgiving".
 This originates from the belief that Vikings were eternally benevolent to those that worked within their halls.
 The name was used to indicate the main occupation of the individual, in a role such as a servant or chamberlain.
 Hall is the 22nd most common surname in the United Kingdom.
 Within the United States, it is ranked as the 26th most common surname.
The now defunct Standard Chemical Company (SCC) of Canonsburg, Pennsylvania, was the first successful commercial producer of radium.
 SCC operated the radium refining mill from 1911 to 1922 on a 19-acre (77,000 m2) plot of land.
 The company supplied radium to the United States Radium Corporation for use in their watch dials.
The United States Radium Corporation was a company, most notorious for its operations between the years 1917 to 1926 in Orange, New Jersey, in the United States that led to stronger worker protection laws.
 After initial success in developing a glow-in-the-dark radioactive paint, the company was subject to several lawsuits in the late 1920s in the wake of severe illnesses and deaths of workers (the Radium Girls) who had ingested radioactive material.
 The workers had been told that the paint was harmless.
 During World War I and World War II, the company produced luminous watches and gauges for the United States Army for use by soldiers.
The step transaction doctrine is a judicial doctrine in the United States that combines a series of formally separate steps, resulting in tax treatment as a single integrated event.
 The doctrine is often used in combination with other doctrines, such as substance over form.
 The doctrine is applied to prevent tax abuse, such as tax shelters or bailing assets out of a corporation.
 The step transaction doctrine originated from a common law principle in "Gregory v. Helvering", 293 U.S. 465 (1935), which allowed the court to recharacterize a tax-motivated transaction.

Question: What kind of substance does Radium Girls and United States Radium Corporation have in common?
Answer: paint