Checked luggage gets lost and it may get damaged. But this may be the first time – and let’s hope it’s the last – that luggage gets preserved.

On Friday, a passenger checked two closed buckets aboard an Alaska Airlines flight from Barrow to Fairbanks without alerting customer service agents that they were filled with dead fish and formaldehyde, according tothe  Alaska Dispatch News.

But the checked buckets may not have been sealed properly and one of the buckets leaked into the cargo hold. 

When cargo workers opened the hold in Fairbanks, they noticed a strong smell, and it wasn’t eau du dead fish. It was the formaldehyde, a colorless gas in solution made by oxidizing methanol that is used as a preservative in mortuaries and medical laboratories. It’s also used as an industrial disinfectant, germicide and fungicide.

It smells awful, and it may cause cancer.

So mixing it with your luggage (or, for that matter, dead fish) is not advised, which is why the 118 bags that were stored in the hold with the two buckets of fish weren’t released to passengers when Flight 55 arrived in Fairbanks.

Instead, the airline brought in a hazmat company to “clean up the spill and test the bags,” airline spokeswoman Nancy Trott said.

How much formaldehyde spilled in the hold had not been determined by Sunday. Trott told the Dispatch News that it was not clear why the fish were being preserved in the chemical and whether the passenger who brought them on board knew the stuff was hazardous.

As of Sunday afternoon, 107 of the bags had been tested, cleared and returned to their owners. Trott said the airline has "reached out to everyone impacted to discuss compensation."