Burned down by Count Olaf
Heimlich Hospital is the main setting in The Hostile Hospital and served as the Baudelaire orphans' temporary home. One half of the building was finished and the other remained an unfinished frame.
The Finished Half
The finished half of Heimlich Hospital was a beautiful place and was where almost all the work was done at the Hospital. It contains all of the things the hospital needs.
The supply closets contain Alphabet Soup, rubber bands, doctors' coats, as well as a sink. In The Hostile Hospital, Klaus and Sunny hide in one of the closets and use the lab coats to disguise themselves as doctors. Later, the Baudelaire siblings hide in another supply closet from the person who looks like neither a man or a woman while the fire rages through the hospital.
The Unfinished Half
The Unfinished Half of Heimlich Hospital consisted of a wooden frame. During the events of The Hostile Hospital, the Baudelaire children slept in this part of the hospital.
Library of Records
The Library of Records was located in the basement, housing information from all over the area. The library had two rooms, with a small antechamber preceding the large filing room, which itself was filled with rows of locked filing cabinets. The ceiling was low and each aisle of cabinets was only big enough to walk single file. Records were deposited through a chute into the room and then filed away by the recordkeeper, Hal.
The library was set on fire by Esmé Squalor and Count Olaf. The fire then proceeded to spread to the rest of the hospital, eventually burning the entire building to the ground. Afterward, Dewey Denouement's partner went to gather the remnants of records for the Hotel Denouement and discovered Hal, bringing him back to the Hotel.
The Stubbed Toe Ward
The Stubbed Toe Ward was a ward in an unclear section of Heimlich Hospital; presumably it was for the treatment of stubbed toes.
Connection to V.F.D.?
While it was never stated in the The Hostile Hospital, in Lemony Snicket's autobiography, Kit Snicket mentions about both the Library of Records and Dr. Montgomery's house being secured places with information. This could mean that the hospital was originally made by V.F.D., but they had left it half-finished; or a volunteer owned the hospital and added the library.
The Baudelaires discover the Snicket file here.