Ah, April Fools’ Day in the workplace. A special time of the year to break free of employee etiquette and slip a whoopee cushion on a coworker’s chair, suspend your cubicle mate’s stapler in Jell-O, or, if you’re a prankster at one chemistry lab in South Carolina, lead everyone in your building to think they may be inhaling extremely poisonous—and potentially deadly—gas.

That’s what occurred last Friday, as described by Reddit user CausticQuandry in the Chemistry community. A chemical technician specialized in electroplating, the redditor posted that while working in the plant, he kept “smelling almonds.”

“My first thought was that somehow potassium cyanide was mixed with hydrochloric acid but, as I am not dead yet, I’m guessing that is not it,” he wrote, adding that his supervisor wasn’t answering his phone.

Several redditors instantly recognized the possible implications of what he had just shared: Hydrogen cyanide (HCN), a fast-acting poison, is a colorless gas that smells slightly like bitter almonds.

The prevailing recommendation: Get out. Now.

CausticQuandry decided to evacuate everyone.

“So around 200 people, including management and corporate, are in the field beside the parking lot just waiting,” he wrote.

Redditors waited for an update. Were the people okay? Are they frantically calling their loved ones? Did emergency responders arrive? What happened?!

Finally, CausticQuandry came back with some news to share.

Redditors agreed.

We’re calling it: Worst April Fools’ Joke of the Year.

To see the full discussion, check out the original Reddit post.