3.6 Roentgen

"Not great, not terrible."

– Anatoly Dyatlov, Chernobyl (2019)

The maximum dosage of radiation that can be accurately measured by a dosimeter rated for 3.6 roentgen. Side effects may include crushing by boilers and debris, pulverizing in a steam explosion, scalding in a steam explosion, crushing by falling pillars, getting instant second degree sunburns, spontaneous vomiting, and a brilliant laser-like beam piercing up into the sky due to the Cherenkov effect.

An explanation for the confused

It's a meme from a miniseries about the Chernobyl disaster. There are plenty of explanations available from Google, but if you insist: the short version is that the dosimeters at the Chernobyl plant were only rated for measuring 3.6 roentgen (an obsolete unit of measuring radioactivity); the good dosimeters were kept under lock and key[1], and were thus unavailable in the initial hours of the disaster. 3.6 roentgen would be plenty bad, but not horrible--roughly speaking, depending on the radiation, it would equate a less then a 5% increased probability of dying of cancer. Later, more accurate measurements suggested 15,000 roentgen of radiation, meaning the initial estimates were off by a factor of 4000[2]. Mixed with Dyatlov's otherwise insane behavior in the hours after the explosion, the entire internet made the man a meme in the aftermath of the 2019 miniseries, with the "3.6 Roentgen" line particularly being widely memed on.

[1] Why yes, the Soviet system was horribly dysfunctional, thanks for asking. [2] For scale, that's a bit like a claim that something is a foot long, when it's actually 3/4 of a mile long; or a claim that something lasted a second when it actually lasted over an hour, or a claim that something lasted an hour when it actually lasted 5 months.