Project Blue Book Photo File Relating to Tremonton Film, Utah, July 2, 1952 — Department of War File
During its investigation of a July 1952 film of an incident reported near Tremonton, Utah, Project Blue Book examined whether the objects recorded on film might have been “pillow balloons.” Project Blue Book was a U.S. Air Force program active from 1952 to 1969 that investigated the nature and…
Incident Overview
On July 2, 1952, in Tremonton, Utah, the Department of War preserved a documentary record that was declassified and published on September 18, 2026 as part of the sixth tranche of the Department of War’s Presidential Unsealing and Reporting System for UAP Encounters (PURSUE).
What the government released
During its investigation of a July 1952 film of an incident reported near Tremonton, Utah, Project Blue Book examined whether the objects recorded on film might have been “pillow balloons.” Project Blue Book was a U.S. Air Force program active from 1952 to 1969 that investigated the nature and origin of unidentified flying objects (UFOs). In December 1952, investigators contacted General Mills, Inc., the only known manufacturer of pillow balloons at the time, to determine whether a balloon release could account for the incident.
The file includes example imagery of pillow balloons supplied by General Mills Research Laboratories. In late December 1952, Project Blue Book personnel, balloon specialists, and representatives from General Mills reviewed the Tremonton footage. The group’s consensus was that the objects closely resembled pillow balloons in flight and behaved consistently with that explanation. One General Mills representative was less convinced, noting that the objects appeared somewhat too bright and seemed to maneuver too rapidly.
The reviewers also questioned previous angular-velocity calculations suggesting that the objects moved at a high rate of speed because those calculations depended on the unverified assumption that the camera operator had held the camera still during filming. Subsequent efforts to identify a pillow-balloon release in the Tremonton area were unsuccessful. The file also considered seabirds as a possible explanation, citing similar films showing seabirds as bright points of light under comparable conditions. Later Air Force assessments favored the seabird attribution.
Related records
The release files this document with Historical Film of Reported UFOs, Utah, the Navy Photographic Interpretation Center film analysis, Project Blue Book File on Tremonton Film, Utah, Final Personnel Record for Newhouse, Delbert C., U.S. Navy, and U.S. Air Force Flying Discs File, which concern the same case. They were produced by different offices at different times, and are best read in sequence.
The case in this archive
This record is a primary source for the Tremonton film of 1952, written up here at length from the contemporary record. The file and the case history are worth reading against each other: the document is narrower and more cautious than the account that grew up around it, which is usually the point.
Status of the case
This is an archival record, and it should be read as one. It records what a particular office believed, or was willing to commit to paper, on the day it was written — not a present-day finding. The mid-century investigations worked from witness testimony, sparse instrumentation, and the strategic anxieties of the early Cold War, and the great majority of the sightings they catalogued were eventually attributed to aircraft, balloons, astronomical objects, and misidentification. The All-domain Anomaly Resolution Office has made no modern determination about the incidents described here, and the record’s release is not an endorsement of the conclusions inside it. Its value is as evidence of how the United States government investigated the question, and of what it chose to keep.