# Is ozone safe to use in my house for smoke odor? No. EPA states that no federal agency has approved ozone generators for use in occupied spaces, and that at safe concentrations ozone is not effective against > Source: https://servpronorhfremont.com/questions/smoke-odor-removal/is-ozone-safe-to-use-in-my-house-for-smoke-odor/ > Last reviewed: 2026-08-22 --- - Home - All questions - Smoke odor removal - Is ozone safe to use in my house for smoke odor? # Is ozone safe to use in my house for smoke odor? - Fire & smoke Professional required This page explains the work. It does not tell you how to do it, because doing it without training and equipment is unsafe. No. EPA states that no federal agency has approved ozone generators for use in occupied spaces, and that at concentrations which do not exceed public health standards, ozone is not effective at removing many odor-causing chemicals. Ozone damages the lungs. It is used only in unoccupied structures, by trained operators. Approved for occupied use No agency Effective at safe levels No What ends odor Residue removal ## The short version - EPA — "NO agency of the federal government has approved these devices for use in occupied spaces." - EPA — at concentrations that do not exceed public health standards, ozone "is not effective at removing many odor-causing chemicals." - EPA — "When inhaled, ozone can damage the lungs", causing chest pain, coughing, shortness of breath and throat irritation. - The concentration that would work on odor is above the concentration that is safe to breathe. That gap is the whole objection. - Odor comes from residue. Removing the residue is what ends it, whatever else is run in the room. ## What EPA actually publishes # Link to this section Four statements, and together they close the question: NO agency of the federal government has approved these devices for use in occupied spaces. Available scientific evidence shows that at concentrations that do not exceed public health standards, ozone has little potential to remove indoor air contaminants. There is evidence to show that at concentrations that do not exceed public health standards, ozone is not effective at removing many odor-causing chemicals. When inhaled, ozone can damage the lungs. Relatively low amounts can cause chest pain, coughing, shortness of breath and throat irritation. The structure of that is worth noticing. It is not only a safety objection. At levels that are safe, it does not work; at levels that would work, it is not safe. Both halves have to be true for a device to be useful in a home, and neither is. ## Why it seems to work anyway # Link to this section Ozone has a strong, distinctive smell of its own, often described as clean or sharp, and it temporarily overwhelms the perception of other odors. It also oxidizes some surface compounds, which produces a real short-term improvement. Then the residue that is still in the sofa, the carpet, the ductwork and the wall cavity continues doing what it was doing, and the smell returns — typically with the first warm, humid weather, because heat and moisture increase the release rate. ## What ends smoke odor instead # Link to this section Residue removal, in an order that matches the residue type. Dry smoke is fine and powdery and travels far, so the search area is much larger than the fire area. Wet smoke is sticky and stains, and wiping it makes it worse. Protein residue from a cooking fire is almost invisible and carries the strongest odor of the four. Fuel-oil soot from a puff-back is oily and acidic. In every case the sequence is the same: get the HVAC system out of circulation so nothing is redistributed, remove residue from hard surfaces and from porous material, deal with what cannot be cleaned by replacing it, and only then consider sealing and repainting. ## Air cleaners are a different thing # Link to this section A HEPA filter captures particulate; an activated carbon filter adsorbs some odor molecules. Neither generates ozone, and neither is what EPA is warning about. They make a house more tolerable during the work and they do not remove residue from materials, so they are a comfort measure rather than a fix. The distinction matters when shopping, because devices that generate ozone are sometimes marketed as air purifiers, and some are sold on the strength of producing what EPA describes as a lung irritant. ## Why this needs a professional Professional ozone treatment exists, and it is a different activity from a device bought online. It is performed in a structure with nobody in it — no people, no pets, no plants — sealed, with the HVAC system isolated, for a controlled period, followed by a controlled airing-out before anyone re-enters. The operator is managing a respiratory hazard on purpose. It is also not a substitute for the work. Ozone is used after residue removal, on residual odor, not instead of removing the residue that is producing it. A structure treated with ozone while the wet smoke residue is still on the walls smells better for a while and then smells again. ## What this means for your claim Odor treatment is a legitimate line on a fire claim, and it belongs in a scope that names the residue type it is addressing. If an estimate contains deodorization but no residue removal, it is proposing to treat a symptom, and the smell will return inside the claim's own timeframe. Keep the sequence documented — residue removal, then any deodorization, then sealing and repainting. If odor comes back after sign-off, that documentation is what makes reopening the claim a matter of record rather than of argument. ## What comes next Odor is residue you have not found. See smoke residue types for which one you are dealing with, and water categories if the fire was suppressed with water, because that changes what else is happening in the same materials. ## Common mistakes - Running a device in an occupied house. EPA is explicit that no federal agency has approved these for occupied spaces. - Treating a room while pets or plants are in it. Both are more sensitive than people to what is being generated. - Using ozone before residue removal, which produces a temporary improvement and no durable result. - Assuming a stronger machine is the answer. The concentration required is above the one that is safe to breathe. - Confusing an ozone generator with a HEPA or carbon air cleaner. Those filter air and do not generate a respiratory irritant. ## Common follow-up questions ### What about ozone in an empty house before we move back in? That is the professional use case — an unoccupied structure, sealed, HVAC isolated, controlled exposure, controlled airing-out. It is still done after residue removal rather than instead of it, and it is not something to run yourself on the basis that nobody is home this weekend. ### Is a hydroxyl generator safer? Hydroxyl generators are marketed as usable in occupied spaces, and they operate on a different principle. EPA's published warning is specifically about ozone. Whatever is used, the same limitation applies — an air treatment does not remove residue from a sofa or from ductwork, and the residue is what produces the odor. ### My contractor wants to ozone the house. Should I let them? Ask two questions and let the answers decide it. Has the residue been removed first, and by residue type. And will the structure be unoccupied, with the HVAC isolated and a controlled re-entry. If the answer to the first is no, the treatment is being used as a substitute for the work rather than as a finishing step. ## Related questions - The first hour after any loss - Smoke residue types and why they differ - What to photograph and log ## Sources Every source cited on this page - T1 Ozone Generators that are Sold as Air Cleaners — US EPA (accessed 2026-08-25) - T2 ANSI/IICRC S700 Standard for Professional Fire and Smoke Damage Restoration — IICRC (accessed 2026-08-25) Written by: PLACEHOLDER — Restoration Reviewer Reviewed by: PLACEHOLDER — Claims Reviewer Safety reviewed by: PLACEHOLDER — Restoration Reviewer Last reviewed: 2026-08-22 Guidance that does not name a water category, a smoke type, or the peril and whether the water was internal or external is not specific enough to act on. This page names them.