The filmmakers had a most practical way of performing the 360 degree panorama shot of the classroom transforming into Langer's torture chamber with actress Josie Maraninside of it. First, the set was built to resemble a classroom. The camera was then brought in and bolted firmly to the ground. The shot was filmed and a protective bag placed over top the camera while the art department made the room into a dungeon. The camera was then unbagged and the shot repeated. Blending the two takes together created a perfect precision transformation. Actress Josie Maran was then superimposed into the scene.
The location used for the Parapsychology institute had been abandoned for years. It had no electricity or running water at the time of shooting. Several large generators had to be brought in to power the sets and camera equipment.
Director Mike Mendez fought against the opening of the film with Oakley Stevenson (his real-life wife) and has said he wished it wasn't in the film, but the sales company said "they gotta know it's a horror movie" and insisted someone die. He was so opposed to the idea that he refused to direct the sequence, which was ultimately directed by producer Al Corley.
During the Director Commentary on the DVD, director Mike Mendez and composer Joseph Bishara played a drinking game every time they saw a lit lamp during the film.
In South Carolina they burn down abandoned and/or condemned houses as opposed to demolishing them and the filmmakers asked if they could use an abandoned house before it was to be burned down. It was used several times throughout filming, as Kira's house and the sets of the pyromaniac ghost.
The hospital was actually a convalescent home and filmmakers received numerous complaints about the loud screaming and dangerous stunts while shooting.
Upon her first reading of the script at 2 in the morning, Megahn Perry was so frightened half-way through the script that she threw it across the room.
The trivia item below may give away important plot points.
Dominic Purcell was literally buried alive and held his breath while waiting for Clare Kramer and Tchéky Karyo to dig him back up. Initially they had trouble finding him.