Declassified FBI Files Reveal 1950s Military Concern Over 'Green Fireballs' Near Nuclear Facilities

In December 1948, Mexico area had grown sufficient to warrant an organized reporting system. This decision, recorded in a 25 May 1950 summary from the Office of Special Investigations (OSI) to Brigadier General Joseph F. Carroll, Director of Special Investigations, marked the beginning of a formal, multi-agency effort to collect and analyze sightings that defied conventional explanation.

The OSI district office, whose units were deemed most suitable for the task due to their location and organization, assumed responsibility for gathering basic information on these phenomena, distributing reports to the Air Materiel Command and other interested military and government agencies. The summary, filed under File No. (24-8)-28, covered observations from December 1948 through May 1950, and its very existence underscores the seriousness with which these incidents were treated.

The sightings were not random or isolated; they clustered near sensitive installations, raising concerns that would persist for years. This coordinated reporting framework,…