Revealed hoaxMaury Island Incident (June 1947)

aka Maury Island Incident (June 1947)

Harbor workers Harold Dahl and Fred Crisman claimed a doughnut-shaped craft over Puget Sound rained slag that killed a dog and injured Dahl's son days before Kenneth Arnold's sighting; the case drew in Arnold and two Army officers who died in a B-25 crash carrying debris, and was judged a hoax.

documented-hoax A well-established hoax: the debris was industrial slag, a claimant recanted, and the FBI and Blue Book judged it false. The fatal B-25 crash was real but mechanically caused. Documented hoax, with lingering folklore.

status history (1)

2026-06-14 · new → documented-hoax — seeded 2026-06-14 — corpus-growth pass (canonical cases the record lacked)

▸ Deep dive — full timeline, named personnel, sensors, theory-by-theory analysis, and the conventional explanations weighed against the open questions →

In late June 1947, at the birth of the modern UFO era, Harold Dahl and Fred Crisman claimed six doughnut-shaped objects over Maury Island, one of which ejected slag-like debris. Pulp publisher Ray Palmer paid Kenneth Arnold to investigate; Army Air Force intelligence officers Frank Brown and William Davidson collected samples and died on 1 August 1947 when their B-25 caught fire and crashed near Kelso, Washington. The FBI identified the ‘debris’ as ordinary industrial slag, Dahl reportedly recanted, and Project Blue Book’s Edward Ruppelt called it ‘the dirtiest hoax in UFO history.’ The crash was real but attributed to engine fire; the case established durable tropes (physical ‘debris,’ menacing visitors, deadly intrigue) while being one of the most thoroughly debunked.

Notable & intriguing

The ‘slag’ was identified by the FBI as ordinary industrial material; Edward Ruppelt of Project Blue Book called the affair ‘the dirtiest hoax in UFO history.’

Ruppelt, The Report on UFOs (1956); Wikipedia
Army officers Lt. Frank Brown and Capt. William Davidson died on 1 August 1947 when their B-25, carrying debris samples, caught fire and crashed near Kelso, Washington - often called ufology’s first fatalities; the cause was engine fire, not sabotage.

HistoryLink; Wikipedia

Public-record items already documented about this subject. Folklore is labelled. Sources cited where the specificity warrants it.

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