The owner of a northeast Calgary Dairy Queen is desperate to solve a mystery about a strange smell in the restaurant.

It all started when the Dairy Queen located on the 11 thousand block of 14 Street Northeast opened in January 2015; the owner walked in and instead of smelling fires and burgers, he smelled a sour gas odour.

“I smell it like propane and sometimes you smell it like hydrogen sulfide or something... sometimes it's just some kind of gas,”says store owner Sujad Bandali.

He contacted Atco and the Calgary Fire Department who rushed out to run tests but they didn’t find any gas leak or any other problems.

There have been multiple tests and inspections since that time and so far no one can find the source of the smell.

“We are really desperate. This has gone on almost two and a half years now and we can't solve this problem,” says Bandali. “It's bothering me so much that I can smell it everywhere now; even when I'm home.”

The staff is divided about whether the smell even exists and only about half the people who come inside actually smell it.

“I honestly don't know what kind of gas that smells like, but it smells like gas,” says customer Ashley Wood.

“I saw the sign and I almost turned around, but for the most part it's been okay,” says customer Jason MacDonald.

The Dairy Queen has posted a sign on the front door assuring people it’s safe but asking for help in sniffing out the source and if you are successful in figuring out what the smell is Bandali will give you free blizzards for a year.

(With files from Jordan Kanygin)