A reason given for having the power washers in the building is to prevent the water from freezing in the unit. An approach to safe operation under freezing conditions includes moving the washer indoors when it is not operating and back outdoors before starting it. Draining the water from the unit after it has been turned off will also prevent freezing problems. No gasoline engine, irrespective of size, should ever be run inside a building. Trying to convey the power washer engine exhaust from inside a livestock building to the outside with a tubing may be inadequate or pose unique hazards such as high carbon monoxide concentrating near the entrance of the building or contamination of the workspace by leaks or holes that could develop in the tubing.
Similar hazards can exist in workshops that are closed against winter weather.
Exhaust fans are only as efficient if fresh air is available from an open window, or from a ventilator installed to provide an incoming source of fresh air to the work area. Farm managers should err on the part of safety because carbon monoxide is such a stealthily killer. Because it is colorless and odorless, carbon monoxide can overcome a person without their knowing what is happening to them. When it is inhaled, carbon monoxide mixes with blood 210 times quicker than does oxygen. Air containing moderate to high amounts of carbon monoxide by volume could lead to unconsciousness in about five minutes.