I talked to a man who worked there. He said he was working a night shift and at around midnight he was eating lunch. He looked up from his meal to see a dog looking at him. It was a friendly dog wagging his tail. The man was annoyed because a dog in the building meant someone left a door open. Still, he decided to share his lunch with the dog. He opened his lunch box to get the dog a bite. When he looked up the dog was gone.
He searched for the dog but never found it. He also didnt find any open doors. Thinking the dog got out and the wind shut the door, his night went on uneventful.
The next day found the man warning everyone to be on the lookout for the dog and to make sure the doors were closed. His co-workers exchanged looks so the man asked what the problem was.
Every hair on his body stood up as they told him that back in the 1930's the building had a more ominous use. Hundreds of stray dogs were euthanized inside on a weekly basis, using carbon monoxide.
The man telling me this story believes he met the ghost of one of those unfortunate dogs.