In the year 2000, officials from Alberta, Canada, declared that their province was finally rat-free.

The first rat invaded Alberta in 1950 and the government has been fiercely battling them ever since. After the rat was discovered on a farm that summer, the Department of Agriculture took swift action launching an all-out offensive.

The first step? Explaining to the people of Alberta what rats are. According to the elaborate History of Rat Control in Alberta page on the Agriculture and Forestry government site, people didn’t even realize that they were under siege:

“Most people in Alberta had had no contact with rats and did not know what rats looked like or how to control them. Consequently, the government’s initial response was to educate the public and obtain support from local governments and residents.”

So they educated their citizens the best way they could: by sending out a bunch of “preserved rat specimens” to agriculture offices. They also reshuffled their workforce, assigning a few weed inspectors to train municipal officers in the art of rat destruction.

Just to be safe though, they also had six rat conferences, put up 2,000 posters and 1,500 pamphlets. The pamphlets were handed out in train stations, schools, post offices, and to any person who would accept one.

The agency didn’t mess around when it came to details on just how to get rid of these creatures:

“Rat Control In Alberta, 1951 advocated destruction of rats, elimination of rat harborages and food supplies, and rat-proofing of buildings principles which are still valid and basic for rat control today. Recommended toxicants were red squill, antu, barium carbonate, zinc phosphide, 1080, thallium sulfate, arsenic, strychnine alkaloid and warfarin. Warfarin, the first anticoagulant rodent poison, was still a new and relatively untried toxicant in 1951.”

The following year, 63,600 kg of “tracking powder”—a substance roughly 75 percent arsenic trioxide—was dumped across Alberta. Eight-thousand buildings on 2,700 farms were treated, much to the dismay of both rats and non-rats alike. Livestock, poultry, pets, and people were affected, along with the budget. The program cost$152,670 in 1952, or $1,370,216 in today’s terms.

But—even after educating the citizens of Alberta on how to beat the imminent threat of rats and dumping expensive toxic chemicals all over the place—the rat-war would last another decade:

“The number of known rat infestations in the border area increased rapidly from one in 1950 to 573 in 1955, and varied between 394 and 637 during 1956 to 1959. After 1959, numbers of infestations dropped dramatically. Hence, almost 10 years passed before an accumulation of training, experience and public education brought the rat problem firmly in hand.”

The rats however, haven’t given up. Rats are, naturally, excellent at survival and the program to combat them is still active today. As user geddup_noise pointed out on Reddit Friday, a dozen rats slip across the borders every year—but are quickly stopped by “provincial rat control specialists before they can breed.”

Sometimes though, rats sneak in undetected. In 2012, 147 rats were found mysteriously living in a landfill. They quickly met the full force of the rat control specialists. According a local newspaper, after winning the battle against the rats, the team was able to return to “their fall patrol of Saskatchewan border areas to ensure no rats make winter homes in Alberta farmyards, granaries, and bale stacks.”

Just last month, the rat-authorities experienced another close call. According to The Huffington Post, a few rats were spotted hiding in a chicken coop.

Officials say they have handled the problem.

The citizens of Alberta can, once again, breathe a sigh of relief while the brave rat patrollers pace the province protecting them from any rat that might dare dip a toe across the border.