Document 3eJz1jv5jd2736zxYG2bppNVx

724 LEON F. CURTISS way, he accumulated information that would provide easy identification of* disease from its symptoms. As a result of this clarification of the picture, itf came evident that deaths of workers at least as early as 1922 had result of radium poisoning, although attributed by family physicians to oti diseases. It is estimated that eventually at least 40 persons died from it' disease. It is of interest to consider the general environment under which these circumstances developed. In the period of World War I and immediately th after, about 800 girls, at one time or another, were employed in one New Jersey as radium dial painters. There were other smaller plants ini around New York City. The considerable demand for radium dials for mill" use caused this rapid expansion of a very small industry, and employees recruited from other types of work where similar skills were required. Usuifl they were paid in accordance with the number of articles completed per and were not warned of any particular hazard, since the dangers fromli ingestion of radium were not then understood. Consequently, they adoj procedures that would enable them to produce acceptable work at theEK rapid rate. Many of these people had applied other types of paint, in pref employment, which were not-sufficiently toxic to produce any ill effects. fine brushes were pointed by means of the lips. They soon discovered was a very effective procedure in radium dial painting. Since the paint conlf chiefly of zinc sulfide suspended in a water solution of gum arabic, occasion thinned with water to give proper consistency, there was no natural detenH the procedure. The amount of radium that a dial painter might ingest these circumstances has been estimated at from 15 to 200 micrograms pen!?1 This explains in a few words how the situation developed. Early in the invgjp tion, the employers sensed that radium poisoning might be the cause sjcifi deaths and injuries, which were rapidly mounting, and ordered the practices tipping brushes with the lips discontinued. However, such a regulation-w difficult to enforce, and it was not until the advent of plastic adhesivesgj|i organic solvents of disagreeable taste and odor that the practice was eliminated. " Although it has been well established that the practice of pointing^., brushes with the lips was the predominant cause of the injuries, there,tarpja'fjf today,' in appafent"'gob'd' health,'"workers'who"ilied thir'methodfoT^flb^f^ years. This fact is mentioned to show that part of the confusion in dfriyinl a solution of the problem arose from individual differences among the employee Those who survived apparently developed a method of pointing the brushesfF -did. nat-r.esult-in_ingeation-.of_appr.eciable-amoun.ts-of-paint.-r-otheis-W.afg;:, careless in this respect. 2. Radioactive Nature of Radium ' Radium is always accompanied by its decay products in amounts dependent on a number of conditions associated with the previous chemical history of i RADIANT ENERGY 712*05 Iparation. The properties of a sample of radium in equilibrium with its decay Ulucts will be more readily understood by reference to Figure 3, which shows ietic relationships in the radium family. We see that the immediate product Iridium is a gas, radon, which decays to half-value every 4 days after removal the source of supply, radium. This transformation is accompanied by the mission of an alpha particle for each atom transformed. By emission of another a, particle, radon becomes RaA, which in the same way transforms into RaB. changes to RaC by emitting a beta particle. Here, a branching occurs that Unites in RaD, which by emitting a beta particle becomes RaE, and this Atomic Number 81 82 83 84 85 86 87 88 RodiumB Radium A Rodon -O- --------O- -oRadlurr Radium C 1600 yeofs Rodium C' Elements represented by shaded circles also emit powerful gomma roysond are the most potent sources of injury produced byolpho and beta rays'. ..Radium E Radium 6 ..Radium F Leod The Rodium Family Figure 3. The genetic relation of various products originating from the transformation of mum. Heavy black arrows pointed horizontally to the left represent the emission of alpha . Diagonal arrows to the right represent the emission of beta rays. Cross-hatched circles |j|resent members that emit strong penetrating gamma rays. tei. ifjpice in. the same, .way'transforms-into RaF'"(pqlbniuih)'. By emitting an iffa. particle, RaF becomes RaG, an inactive isotope of lead. The cross-hatched firjpl.es represent elements that emit the more powerful gamma rays associated ;|h:radium. Thus we can see that radon, even-after removal frpfia. radium, will Ssbeiated^-ith--i.tE-the^pr.odu&ts-eimtting-the more .powerful-radii Jipiible of producing injury. The quantitative relation between the radon Ipferated in a given time and the amount of the parent radium,,can be used, to nlfsure the amount of radium present by measuring the rate of production of Son.