Alberta’s status as being rat-free could be in jeopardy after more than a dozen Norway rats were discovered at a landfill in the southeast corner of the province.

Agriculture Minister Verlyn Olson announced the discovery of the rat colony during a news conference Wednesday at the Medicine Hat regional landfill.

The province prides itself on being rat-free, and has only seen isolated cases of the rodents since the 1950s.

“We want this dealt with as quickly as possible and we’ll keep at it until the issue is resolved,” Olson said.

The 19 rats were found last Thursday and all have been killed, but officials are worried there could be more.

Traps and infrared digital cameras have been set up at sites around the dump.

Jason Storach, an agricultural fieldman with the local county, said finding so many rats in Alberta is highly unusual.

“I’ve been working for Cypress County for five years and we’ve never experienced anything close to this,” Storach said.

“For many years previous to this, it’s been one or two rat calls, and one of those will be a muskrat and one of those will happen to be a rat that jumped off a truck somewhere.”

Agricultural fieldmen, known by Albertans as the “Rat Patrol,” eliminate invading rats within a control zone 600 km long and 30 km wide along the province’s eastern boundary.

The rat eradication program was implemented in the early 1950s following an outbreak of Norway rats near Alsask, in central Alberta, according to Alberta Agriculture’s website.

On the program’s anniversary in 2002, the government estimated that $1 billion has been saved over 50 years in potential property damage, livestock losses, human suffering and health care, as well as lost and contaminated food.

The province says one pair of rats can thrive and begin a chain reaction of breeding that can produce as many as 15,000 offspring by the end of a year, as long as they are close to food and sheltered from the weather and predators.