Abstract: An environmental protection apparatus for protecting an opening such as windows, doors, airbricks, cat flaps, tumble dryer vents, meter cupboards, etc. against flood water. The apparatus includes a removable envelope arranged to surround the opening, a seal for sealing the envelope to the opening, and an attachment for releasably securing the envelope to the opening. The envelope is a box having a open side, positioned adjacent to the opening. The seal peripherally surrounds the open side of the box. The seal is a compressible material arranged to be compressed between the box and the opening. The attachment is an apertured plate securable to the opening. The releasable attachment is a hook arranged to be secured to the opening and an inter-engageable aperture in a portion of the box structure.