You do not want to be a white-noser.

It would just lead to erratic behavior and eventually death, according to the Center for Biological Diversity. The eastern U.S. bat population is taking on the mysterious white-nose syndrome and losing at an alarming rate. The disease, which is characterized by an actual white nose, ears or tail, affects bats during the winter months and is causing them to leave caves in the middle of the day. Since the night fliers are supposed to be in hibernation, fat levels are low and the unscheduled activity usually leads to death.

The threat to the group, which contains some classes on the federal endangered species list, has led conservation outfits to file a letter of intent to sue several federal agencies, including the Federal Highway Administration.

“We’re not trying to shut anything down,” Mollie Matteson, conservation advocate for the Center for Biological Diversity, told Roads & Bridges. “We are not trying to stop anything. We are just saying that the species is taking a big hit and that the federal government needs to go look at these [future] projects and reconsider them.”

But the causes of white-nose syndrome are unknown. According to the U.S. Fish & Wildlife Service website, nobody knows how the disease is spread. The New York Department of Environmental Conservation is spearheading an investigation into the workings of the white-nose syndrome.

“They are scrambling,” said Matteson. “They are doing toxicology studies and looking at bacteria, viruses, and they haven’t found anything.”

“If you do not know [the cause or how it is spread] the first response should not be to shut down every transportation project in the Northeast,” Nick Goldstein, assistant general counsel and director of regulatory affairs for the American Road & Transportation Builders Association, told Roads & Bridges. “There is not even a causal link there, yet you can threaten transportation projects?”

Even though bats have been seen with this disease only in the wintertime, conservation groups are concerned about activities—like logging and road building—that affect habitats in the summer.

The syndrome has been confirmed in bat caves in Connecticut, New York, Vermont, Massachusetts and three different counties in southwest Pennsylvania. The Indiana brown bat has suffered the most fatalities because of the fungus, but other endangered bats, like the gray bat, the Ozark big-eared bat and the Virginia big-eared bat, have yet to be observed with the disease.

Conservation groups can officially file suit 60 days from the letter of intent. The U.S. Fish and Wildlife Service, U.S. Forest Service, Army Corps of Engineers, National Park Service, Tennessee Valley Authority and Department of Defense also have been blamed for the white-nose syndrome.

The ease of filing lawsuits has been an ongoing concern in the transportation industry. SAFETEA-LU does carry a 180-day statute of limitations on when lawsuits can be filed, but more work needs to be done.