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On Wednesday, October 14,1959, at approximately 13:32, four men working on a scrap disposal crew were killed during a routine operation at the Los Alamos Scientific Laboratory’s S-Site burning ground. The cause of death was the accidental explosion of an estimated three hundred pounds of explosives.
The lattice parameter of cubic chemical vapor deposited (CVD) ZnS with measured oxygen concentrations < 0.6 at.% and hydrogen impurities of < 0.015 at.% have been measured and found to vary between -0.10% and +0.09% relative to the reference lattice parameter (5.4093 Å) of oxygen-free cubic ZnS as reported in the literature. Defects other than substitutional O must be invoked to explain these observed volume changes. The structure and thermodynamic stability of a wide range of native and impurity induced defects in ZnS have been determined by Ab initio calculations. Lattice contraction is caused by S-vacancies, substitutional O on S sites, Zn vacancies, H in S vacancies, peroxy defects, and dissociated water in S-vacancies. The lattice is expanded by interstitial H, H in Zn vacancies, dihydroxy defects, interstitial oxygen, Zn and [ZnHn] complexes (n=1,…,4), interstitial Zn, and S2 dumbbells. Oxygen, though present, likely forms substitutional defects for sulfur resulting in lattice contraction rather than as interstitial oxygen resulting in lattice expansion. It is concluded based on measurement and calculations that excess zinc atoms either at anti-sites (i.e. Zn atoms on S-sites) or possibly as interstitial Zn are responsible for the relative increase of the lattice parameter of commercially produced CVD ZnS.
Early in the afternoon of October 14, 1959, routine operations at the S-Site Burning Ground of Los Alamos Scientific Laboratory were interrupted by the unanticipated explosion of approximately 300 pounds of high explosives. Tragically, the four men preparing the area for the burn operation were killed instantly: Jose Cordova, Sevedeo Lujan, Escolastico Martinez, and Leopoldo Pacheco. Significant effort was exerted to gather the debris and reconstruct the conditions at the time of the accident. Photographs were included in the official accident report with explanatory captions. A few of these photographs were shown on February 12, 2013 in a public lecture for the Los Alamos Historical Society. Afterwards, children of the deceased expressed an interest in having clear copies of the photographs. This document serves as an official mechanism for their release.
On the evening of February 24, 1959, routine operations at the S-Site explosives machining building of Los Alamos Scientific Laboratory were interrupted by the unanticipated explosion of approximately 7.5 pounds of high-energy explosives. Tragically, two men working in Building TA-16-260, Bay 2, were killed instantly: Leo Guerin and Ray Means.