It caught my eye because it was workwear related, and workwear is a highly collectible genre of vintage clothing. But when I also noticed it was marked "Union Mills, Hudson, NY", I sprung for the $3 and brought it home.
Googling led me to the New York State Archives website, where there was a page about fire safety investigations that were launched all over New York after the tragic Triangle Shirtwaist Fire in March of 1911.
This is one of the three interior photos of Union Mills, Hudson New York, taken sometime between 1911-1915.
It shows the plant on Washington Street, which is probably the building we know today as the pocketbook factory.
Other photos of Union Mills, Hudson, give locations on Fulton Street (the northern Front Street mill building?) including the one of the girl working five feet away from foul-smelling water closets.
All three pictures in their entirety--with their details --can be found