Homer Police Sgt. Lary Kuhns said the employee had started to clean it up, but realized that the mess may have been caused by something unusual and contacted police.
Kuhns said an investigation revealed that a homemade bomb had been detonated in the restroom sometime between noon Thursday and Friday.
"If somebody had been inside, they would have been at least injured," and could have been killed, Kuhns said.
Kuhns declined to release details about the bomb because the case was still under investigation, but said it could have been constructed with materials from a hardware store. He has contacted the federal Bureau of Alcohol, Tobacco and Firearms.
Kuhns said since no one reported the blast, it is likely the bomb was detonated when there were few people in the area, but one concern is that the person might have been testing the bomb. "The fact that it happened in a public place is cause for alarm," he said.
Kuhns encourages anyone with information about the bomb to contact police.