A bar in Washington D.C. has been slammed with a $90,000 fine after a customer was served a potentially lethal cocktail containing a chemical nicknamed “yellow death."

On the night of Nov. 11, 2018, Leon Williams was at Club Heaven and Hell, in the city's Adams Morgan neighborhood, where he ordered his favorite cocktail, a Long Island iced tea. But upon taking his first sip, Williams knew something other than the normal ingredients had been added to his drink.

BOY, 11, WITH TERMINAL BRAIN CANCER ASKS FOR ‘PATCHES AND PRAYERS’ FROM MILITARY, LAW ENFORCEMENT, FIRE COMMUNITIES

"When I first drank it, I was like, 'Man, this ain't right,'" he told Fox 5 at the time. "I got up, I told him to taste this drink, then I saw a bottle behind the counter. I grabbed it and it was that clear, bright stuff — that poison stuff that he put in my drink."

Williams had received what could have been a lethal cocktail made with Foam-Brite Condenser Coil Cleaner, a cleaning product sometimes nicknamed "yellow death” due to its color. He was then hospitalized, having suffered chemical burns to his throat.

Now, bar owner Mehari Woldemarian has been hit with a hefty fine after the Alcoholic Beverage Regulation Administration found that this was just one of many code violations and security problems plaguing the establishment, Fox 5 reported separately.

In addition to having to pay the $90,000 fine, Woldemarian has had his liquor license suspended for 90 days.

CLICK HERE TO GET THE FOX NEWS APP

"God as my witness … It was a mistake — why should I have somebody poisoned? The customer comes to pay me and I've been in this business for the longest time in Adams Morgan,” Woldemarian told the station at the time.

The strong cleaning product warns against indoor use and has a label on the cap that cautions of severe skin burns and possible eye damage.