Hundreds of thousands of minks infected with a mutated strain of the coronavirus reportedly rose from their graves.
The minks, culled by the government to prevent the spread of the disease, were pushed to the surface as a result of improper burial procedures.
Residents near the town of Holstebro in Denmark said they saw thousands of dead minks coming out of the ground. Experts believe that the minks were likely pushed to the surface by gases that were formed during decomposition.
Earlier in November Demark approved the culling of more than 17 million minks believed to be infected with a mutated version of the virus. Health authorities said there was a risk of the virus strain making its way to humans.
According to news reports, government workers chose to dig mass graves that were 3 feet deep. That wasn't deep enough.
Elected officials in Denmark's western region said that the botched burial was a "public health nightmare." One of the sites was near a lake and environmentalists fear the decomposing animals might contaminate nearby water. The decomposing carcasses might cause nitrogen and phosphorus pollution, one expert said.
"The authorities are playing with our environment and using it as a dumping ground," one local politician said.
Denmark's environment ministry said that the botched burial was a "temporary problem" and that animals should decompose with no effects on the environment. The ministry did say the animals should have been buried at least 5 feet deep.
The ministry will build a fence around the sites and workers will monitor the areas.