Fumigation: Definition, How It Works and Why It Matters

What fumigation means for a homeowner

Pest control by gas is the simplest way to describe fumigation. The EPA defines fumigants as pesticides that produce a gas or vapor to destroy pests, for example in buildings or soil ⁴. For houses, that usually means “tenting”: the home is covered with tarps, filled with gas, then aired out ¹.

Its main use in homes is drywood termites. These termites live deep inside wood, have small colonies spread through a structure and are hard to find ². A gas fills every space, so it reaches colonies no inspector found.

For residential structures, the only registered fumigant is sulfuryl fluoride. The EPA lists its targets as termites, powderpost beetles, old house borers, bed bugs, carpet beetles, moths, cockroaches, rats and mice ¹.

How a structural fumigation works

This is the general sequence the EPA and UC IPM describe. The label sets the exact steps.

1. Prepare. Occupants, pets and plants leave. Gas pilot lights must be put out ².
2. Seal. The structure is covered with a tent to hold the gas ¹.
3. Post warnings. No-entry warning signs are posted so no one enters the tent ¹.
4. Introduce the gas. The fumigant is released inside. In a monitored fumigation, gas lines inside the house measure the level, which gives the highest success rate ².
5. Hold. The gas stays in long enough to reach a lethal level in the wood. Sulfuryl fluoride kills drywood termites within several days ².
6. Aerate. The tent comes off and the structure is aired out, with longer active and passive aeration now required for homes ¹.
7. Clear. The inside air is tested with a clearance device to confirm the gas is at or below the EPA clearance level before anyone returns ¹.

Types of fumigation and how they differ

For homes, the choice that matters most is monitored versus non-monitored. Ask which one is in your quote.

Example: whole-structure vs spot treatment for drywood termites

This compares the two approaches UC IPM describes for the same house with drywood termite pellets in two rooms. It shows trade-offs, not a recommendation for any one home.

UC IPM advises homeowners to understand the difference between whole-structure and localized treatment before choosing, because the methods are not equal ².

Where you will see fumigation on paperwork

On a termite inspection report, an inspector may recommend “fumigation” or “whole-structure treatment” when drywood termites are found in several areas or the extent cannot be seen. See wood-destroying organism inspections for what those reports contain.

On a fumigation contract and notice, look for the fumigant name, whether the job is monitored, the dates you must be out, what you must bag or remove, who confirms clearance and what the guarantee covers. Our termite warranties and bonds page explains guarantee terms.

At the site, required no-entry warning signs are posted on the tent, and the company keeps a site-specific fumigation log for residential jobs ¹.

In a home sale, fumigation often shows up as a termite clearance item. Our guide to pest control contracts covers the lines to read.

What fumigation does well

• Treats every infestation at the same time, including hidden ones ².
• High efficacy when correctly applied and monitored ².
• Leaves no chemical residue in the home ².
• Reaches pests in furniture, walls and attics that sprays cannot reach.
• One fumigant covers many pests, from termites to bed bugs and rodents ¹.

Drawbacks of fumigation

• Everyone must leave for several days, with plants and pets ².
• No residue means no protection from new termites that arrive after the job ².
• Tarps dragged on a roof, or people walking on it, can damage it ².
• Non-monitored jobs may not reach a lethal gas level ².
• UC IPM notes sulfuryl fluoride has recently been labelled a greenhouse gas ².

What drives fumigation cost

We do not quote prices; a fair figure needs many dated local quotes. These are the drivers.

Building volume matters most, because it sets how much tarp and gas is needed and how long you are out ². Roof type and access affect tenting labor and the risk of roof damage.

Monitoring adds equipment and time but improves the chance of success ². Your own costs count too: a hotel stay, pet boarding and removing plants.

Ask how long the termite guarantee runs and whether an annual inspection is part of it; UC IPM suggests reading the guarantee carefully and considering annual inspections ². Our termite treatment cost estimator compares methods, and the cost guide covers quote structure.

What the homeowner does, step by step

The company leads the job, but you have tasks. Your contract and the product label are the final word.

1. Confirm the need. Get a licensed inspection; ask whether a localized option would work ².
2. Read the notice. Note dates, who to call and what must be bagged or removed.
3. Plan to be out. Book a place to stay for people and pets for several days ².
4. Remove plants and prepare. Plants must leave too ²; arrange for gas pilots to be put out ².
5. Stay off the site. Respect the no-entry signs at all times ¹.
6. Return only after clearance. Wait until the company confirms the air tested at or below the EPA clearance level ¹.

Fumigators are licensed by the state, often in a separate fumigation category. See how pest control licensing works and check the company with the license lookup tool.

After fumigation: keeping termites from coming back

• Remember fumigation has no lasting residue; new swarmers can start fresh colonies later ².
• Watch for new six-sided fecal pellets; clean up old ones and check a few days later to see if new ones appear ².
• Keep up an annual inspection, as UC IPM suggests ².
• Seal and paint exposed wood, and fix damaged wood.
• Keep the paperwork, including the fumigation log reference and guarantee.

Signs you need fumigation, and fumigator red flags

• Drywood termite swarmers in summer or fall, or six-sided pellets piling below small holes ².
• A company that will not say whether the job is monitored.
• No posted warning signs or no lock on the tent.
• Pressure to re-enter before clearance is confirmed.
• Smell, headache, nausea or breathing trouble after returning; leave and seek care.

Federal and state rules for fumigation

Restricted use. Sulfuryl fluoride is a restricted use pesticide: only a certified applicator, or someone under their direct supervision, may use it ¹.

June 2023 early mitigation decision and July 2024 labels. The EPA required new label measures for residential fumigations: posted no-entry signs, site-specific fumigation logs, more stewardship training, a list of effective clearance devices kept on the EPA website instead of “approved” devices on labels, and longer active and passive aeration.

The EPA approved the amended labels on July 11, 2024; older-label stock could be sold for 12 months from that date ¹.

Registration review. Sulfuryl fluoride and all its uses remain under registration review, the EPA’s 15-year re-evaluation ¹⁵.

Labels and states. Labels are enforceable under FIFRA and 40 CFR Part 156 ⁶. States license fumigators and may add rules; in California, state law sets minimum termite inspection requirements ². See the pesticide safety guide.

Fumigation vs heat vs local treatment

See heat treatment for how heat works on bed bugs, and the termite control service page for all methods.

Fumigation myths

Myth Fumigation protects the house for years.

Reality It leaves no residue, so it does not stop new infestations ².

Myth Once the tent is off, it is safe to go in.

Reality Re-entry waits for aeration and a clearance test; deaths have happened after homes were “cleared” ¹.

Myth It works on subterranean termites.

Reality UC IPM says subterranean termites cannot be controlled by fumigation, because their nests are in the soil ³.

Myth All fumigations are the same.

Reality Monitored jobs have the highest success; non-monitored ones may fail ².

Myth I can use foggers to do the same thing.

Reality Structural fumigants are restricted use and applied only by certified applicators ¹.

Where fumigation is most common

When it matters to you, and what to do next

Fumigation is worth considering when drywood termites are in several areas, the extent cannot be seen, or a localized treatment already failed. It is not the answer for subterranean termites, which need soil or bait treatments ³. For a single, reachable board, ask about localized treatment or wood replacement.

Get more than one inspection. Ask each company: monitored or not, how long you will be out, what you must remove, how clearance is confirmed, and what the guarantee covers. Our termite inspection service page and the guide to choosing a pest control company help you compare.

Related terms

Drywood Termite

A drywood termite is a termite whose whole colony lives inside a piece of dry, sound wood, with no need for soil contact, and which pushes small, six-sided fecal pellets out of the wood through tiny holes.

Termite Swarmers

Termite swarmers are the winged males and females, called alates, that fly out of a mature termite colony once a year to pair up, shed their wings and start new colonies.

Powderpost Beetle

A powderpost beetle is any of several small wood-boring beetles whose larvae tunnel inside dry, seasoned wood and pack the tunnels with fine, flour-like powder, leaving tiny round exit holes when the adults emerge.

Wood-Boring Insect

A wood-boring insect is any insect that chews tunnels into wood to feed, nest or develop, including powderpost beetles, the old house borer, forest borers that emerge from new lumber, and some ants, bees and termites.

Subterranean Termite

A subterranean termite is a termite that lives in a colony in the soil and travels to wood above ground through tunnels and mud tubes, eating the wood from the inside while staying hidden.

Termite Baiting System

A termite baiting system is a ring of stations set in the soil around a building that hold wood or cellulose laced with a slow-acting insecticide, so foraging subterranean termites eat it and share it until the colony dies.

Insecticide

An insecticide is a pesticide made to kill, harm, repel or otherwise control insects, and under U.S.

Pesticide Label

A pesticide label is the printed or attached text on a pesticide product, accepted by the EPA at registration, that states what the product contains, how toxic it is, which pests and places it may be used on, how much to apply, and how to store and dispose of it.

Also referenced from: Drywood Termite, Powderpost Beetle, Wood-Boring Insect, Termite Baiting System