An Open Door Does Not Make a Generator Safe Indoors

Controls to confirm

• Keep the engine outdoors: never operate a fuel-powered portable generator inside a building or an enclosed or partly enclosed space. An open door, window or fan does not make an indoor position acceptable. If the proposed location cannot provide safe outdoor operation, arrange another power source before starting work.
• Separate exhaust from occupied spaces: keep the generator more than 20 feet (about 6.1 metres) from doors, windows and vents, following CDC guidance. Check nearby cabins and adjoining buildings as well as your own work area. Keep the manufacturer's required ventilation clearances; OSHA advises 3 to 4 feet of clear space around and above the unit. Follow any stricter manufacturer or local requirements.
• Respond immediately to suspected exposure: headache, dizziness, nausea, unusual tiredness or confusion near a running generator may indicate carbon monoxide poisoning. Move to fresh air immediately, alert others and call emergency medical help. Do not enter a suspect atmosphere to retrieve equipment or rescue someone without trained, properly equipped responders. Re-entry must wait until competent responders establish that the area is safe.

Today’s action

Before today's portable generator starts, walk its proposed location with the supervisor. Measure separation from openings, confirm outdoor airflow and agree the emergency response. Move an unsuitable setup before connecting the load.

Source guidance

Authoritative guidance checked 19 October 2026. Apply the legal requirements and approved procedures for your location.

• US OSHA — Portable generators: outdoor placement, ventilation clearance, poisoning symptoms and safe re-entry
• CDC — Carbon Monoxide Poisoning Basics: invisible, odourless hazard; never run generators indoors even with doors open; more than 20 feet from openings
• CDC — Use a Generator Safely: outdoor separation from doors, windows and vents