Technical report was prepared by the Health and Safety Laboratory (HASL) with the objective of presenting a current picture of the Strontium Program. Abstract: Strontium 90 levels in fallout, milk, canned fish and tap water are summarized for data available up to May 1, 1958. Original data submitted during the month of April are included as an appendix. Data are presented to show the amount of Strontium 90 in fallout at sampling stations within and outside the United States.