When the shit hits the fan
What's the meaning of the phrase 'When the shit hits the fan'?
'When the shit hits the fan' alludes to the messy and hectic consequences brought about by a previously secret situation becoming public.
What's the origin of the phrase 'When the shit hits the fan'?
This expression alludes to the unmissable effects of shit being thrown into an electric fan.
The phrase is known in print in the 1940s and electric fans were invented in the 1880s, so it is very likely to have been coined between those dates. It is difficult to trace in the usual printed sources as it isn't the kind of expression that would appear often in newspapers or novels.
It appears to have originated in the 1930s. I can't say better than 'appears' as, although a usually reliable source places the phrase in the 1930s, the earliest example of it in print that I know of is in Gyrene a novel by the American writer W. D. Jones, circa 1943:
Having been there when the shit hit the fan.
William Daniel Jones was an interesting character as, before taking up writing, he was that all-American stereotype, a gangster. In fact he was part of one of the most celebrated gangs: he was a partner in crime of Bonnie (Parker) and Clyde (Barrow). The Gyrene of the book's title was US military slang for a member of the US Marine Corps - probably an amalgamation of GI and marine.
Jones brought the phrase to the public's attention but he clearly didn't coin it himself. It was well enough known to the American military for a spoof of it to have been used in a song title in 1946. That's the year that John La Cerda published a mémoire of the US war in the Pacific - The conqueror comes to tea: Japan under MacArthur, in which he referred to the song - The Shinto Hit the Fan.
The British soldier and writer Martin Clemens reports hearing the expression used by US military on Guadalcanal in 1942.
The 1967 edition of Eric Partridge's A Dictionary of Slang and Unconventional English lists the phrase as Canadian, circa 1930.
As neither Clemens nor Partridge give supporting evidence we have to go by the 1943 date - although it is probably earlier, as there are several WWII era citations which have variants of the phrase. These more polite forms of the phrase, which involve eggs, pie, soup and 'stuff' hitting the fan, can certainly be dated from the USA the 1940s; for example, Max Chennault's Up Sun, 1945:
"Sounds like the stuff was about to hit the fan."
The Fresno Bee Republican, May 1948, reported on a psychiatrists' convention, under the heading See How Brain Boys Also Run Wild:
"However, once that opening point was settled, the psychiatrists entered wholly in the business of the convention, which culminated, of course, in the selection of officers for the coming year. And that, as the saying goes, was when the soup hit the fan."
The significance of a phrase in the language can often be measured by the number of variants it spawns. With this one the variants are mostly bowdlerised versions of the explicit original - for example, 'when the solids hit the air conditioning', 'when the pooh hits the punka wallah'.