Maple syrup producers in Quebec found themselves in a sticky situation after thieves made off with millions of dollars worth of the breakfast sweetener that had been stored in a warehouse.

Empty barrels were found at a warehouse that had held some 10 million pounds of syrup worth an estimated $30 million, indicating that the thieves had emptied syrup into other containers to sell on the black market.

Provincial police said they had opened an investigation into the theft, adding that the stolen syrup could be worth millions of dollars.

“The Federation always acts with caution to protect producers’ harvests. The St-Louis-de-Blandford warehouse had been secured by a fence and locks, and visited regularly,” Serge Beaulieu, head of the Federation of Quebec Maple Syrup Producers, said in a statement on Wednesday.

“The marketing of the stolen maple syrup will affect the entire maple industry. It is crucial to identify those responsible for this crime,” the federation, which represents some 10,000 maple syrup producers, said.