Three London Underground stations were evacuated because workers burnt toast in the staff room.
Victoria, Oxford Circus and Wood Lane were shut on different occasions in recent years because employees' toast set off fire alarms.
Edgware Road station was evacuated after a workers' e-cigarette set off a fire alarm in the staff room, according to the Evening Standard, and a "suspicious device" that sparked a security alert at Sloane Square turned out to be a brew-your-own beer kit.
The official report for the evacuation at Oxford Circus – one of London's busiest stations – read: "Smoke in station ops (operations) room due to burnt food in toaster in mess room," while the one for Victoria, another major station, said: "Burnt toast in mess room had activated fire alarm."
The bizarre disclosures were made in response to a Freedom of Information request made by Tony Devenish, Tory London Assembly member for West Central.
His findings, reported in the Evening Standard, show that 1,000 stations in Westminster, Kensington & Chelsea and Hammersmith & Fulham were closed between February 2014 and February 2017.
Tube stations in these boroughs were closed for a combined 5,300 hours, or 222 days, during the three year period. This does not include genuine safety and security alerts.
The majority of the closures – 41% – were the result of industrial action. The next biggest cause was staff shortages.
Devenish told the Standard: "Safety and security on London's Tube network is of the utmost importance and so it is right that staff take seriously all incidents where alarms are triggered or suspicious items are found.
"One of the biggest complaints I hear from my residents is unexpected closures of their local Tube stations and with almost 800 non-emergency closures in three years it's easy to see why.
"Sadiq Khan's policies are unlikely to tackle the stations three leading reasons for closures – industrial action, non-availability of staff and defective lifts.
"He is already on course to have the worst strikes record of any London Mayor and his £640 million partial fares freeze could impact on infrastructures such as lift upgrades."
A spokesman for the Mayor of London said: "These claims are absolute nonsense. Of the five instances of industrial action in these figures, four took place while Boris Johnson was Mayor and before Sadiq was elected.
"The overall number of days lost to strike action has actually fallen by 40 per cent since Sadiq became Mayor.
"He also ordered a review into the previous mayor's approach to staffing stations, and as a result TfL is introducing at least 650 new station staff members to the Underground this year."