The Chemical is an extremely corrosive item that Harry Mason can pick up in Silent Hill, found in the Lab Equipment Room located on the second floor of Midwich Elementary School. He must use it to burn a false hand and thus solve the Old Man's Hand puzzle. Doing this gives Harry a gold medallion to put into a slot found on the clock tower outside.
- In the first demos of Silent Hill, a background image was shown when picking up the chemical. It seems that Team Silent planned to use an image for each of the important objects picked up in the game, though this idea was later discarded in the final version.
- Also in those demos, the chemical was originally named "sulfuric acid" according to the label, but it was later changed to "concentrated hydrochloric acid" in the final game. Hydrochloric acid is actually a product of sulfuric acid, and also more acidic.