The owner of a Calgary fast-food restaurant is seeking a sniffing sleuth to help him find the source of a mysterious foul smell that has been plaguing the business for years.

Sujad Bandali says the Dairy Queen location he operates on 14 Street Northeast has had a pungent scent since the day it opened in January 2015.

“I smell it like propane and then sometimes you smell it like hydrogen sulfide kind of thing and sometimes it’s just some kind of gas,” he told CTV Calgary on Monday.

The Calgary Fire Department and the natural gas company Atco have tested the restaurant for leaks on several occasions, but they yet to find one.

Bandali says he can’t stand the inexplicable odour any longer.

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

In an effort to solve the putrid puzzle, Bandali has appealed to the public for help in locating the source of the smell. As a reward, the Dairy Queen will give the successful smeller one free Blizzard treat per week for a year.

Although the restaurant’s staff is divided about the odour’s existence, Bandali says some customers have left because of it.

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

Another customer says he doesn’t mind the baffling scent.

“For the most part, it’s been okay,” Jason MacDonald said. “I don’t smell anything too poisonous.”

Bandali says he just hopes someone will be able to solve the mystery.

“We are really, really hoping somebody can come up with a solution for us,” he said.

With a report from CTV Calgary’s Jordan Kanygin