From Abstract: "This report is one of a sequence of quarterly reports, each designed to up-date its predecessor beginning with HASL-42, "Environmental Contamination from Weapon Tests". Herein are presented data which have accrued since HASL-55. Levels of strontinum-90 in fallout, milk, air, water, vegetation, foods, and bone are given, based on data available from February 1, 1959 to May 20, 1959."

Abstract: This monthly progress report covers the activities of the Army Gas-Cooled Reactor System Program for April 1959. The program includes a water-moderated heterogeneous reactor (Gas-Cooled Reactor Experiment I), a graphite-moderated homogeneous reactor (Gas-Cooled Reactor Experiment II), a mobile gas-cooled reactor (ML-1), and the coordination of the Gas Turbine Test Facility. [It reports] the progress of each project, the associated tests and data evaluation, the applicable design criteria, and the fabrication of reactor components" (p. 1).

Introduction: This document describes the results of a six-week conceptual design study of an organic moderated and cooled reactor (OMCR) power plant adapted to a Class T-7 tanker.