Wildfire Smoke and Ash Cleanup at Home

Why Wildfire Ash Is Different From Fireplace Ash

Ash from a campfire is mostly burned wood. Wildfire ash that falls on neighborhoods is a mix of burned vegetation plus whatever else burned, including homes, cars, plastics, treated wood, paint, electronics and household chemicals. Wildfire ash can hold heavy metals such as lead and arsenic, and ash from burned buildings can contain asbestos.

The biggest risk is the fine particles you cannot see. They stay airborne easily and can reach deep into the lungs. Ash also becomes alkaline when it mixes with water, so wet ash on skin can cause irritation and even burns with long contact. Rinse it off with plain water.

There are two very different situations. The first is ash that drifted onto a home that did not burn. That is the focus of this guide and is a careful DIY job. The second is the ash and debris where a home burned. That is hazardous material. After large fires, cleanup of burned lots is usually handled through organized government programs or licensed contractors, and you should not dig through it on your own.

Protect Yourself Before You Start

Wait until the fire is contained and the air quality in your area has improved before you do outdoor cleanup. If the air quality index is above 150, stay inside and let the ash sit a little longer.

• Respirator. Use an N95 or P100 respirator that seals to your face. Cloth masks, surgical masks and paper dust masks do not protect you from fine ash. Beards break the seal.
• Eyes. Wear goggles, not just glasses.
• Skin. Wear gloves, long sleeves, long pants, socks and closed shoes. Change and wash your clothes as soon as you finish, separate from other laundry.
• Who should not help. Children, pregnant people, older adults, and anyone with asthma, COPD or heart disease should stay away from ash cleanup.

Keep pets inside or away from ashy areas. Ash on paws gets licked and swallowed. Wipe their paws and coat with a damp cloth if they walk through it.

Outdoor Cleanup Without Stirring It Up

The rule outdoors is simple. Keep ash damp and keep it still. Anything that makes ash fly, such as a leaf blower, a stiff broom or a dry shop vacuum, puts the most dangerous particles right back into the air you and your neighbors breathe.

1. Lightly mist the ash with a hose on a gentle shower setting or a pump sprayer. You want it damp, not flowing.
2. Gently sweep the damp ash into piles with a soft broom, or scoop it with a flat shovel.
3. Bag it in heavy duty plastic bags, tie them closed and put them in the trash, unless your city gives other instructions.
4. Wipe patio furniture, railings and play equipment with a damp cloth and mild detergent.

Do not wash ash into the street or storm drains. Storm drains flow straight to creeks and the ocean without treatment, and many cities ask residents to keep ash out of them. Use as little water as it takes to keep the dust down.

Rinse vegetables and fruit from the garden well before eating them, and peel root vegetables. Wash children’s outdoor toys before they are used again.

Indoor Cleanup

Even with windows closed, fine ash and smoke residue get indoors through gaps, vents and on shoes and clothes. Clean from the top of each room down.

• Vacuum with a HEPA vacuum only. A regular vacuum without a true HEPA filter blows fine particles back into the room. Vacuum floors, rugs, upholstery, window sills and tracks slowly.
• Damp wipe hard surfaces such as counters, tables, shelves and floors with a microfiber cloth and mild detergent. Rinse the cloth often.
• Wash curtains, bedding, pillows and throw blankets.
• If you see visible soot or a gray film on walls, dry clean with a soot sponge before any wet cleaning.
• Clean or replace air purifier prefilters and change the HVAC filter after the smoke event.

Leave shoes at the door for the next few weeks. That one habit keeps a lot of ash out of carpets. If smoke odor stays in the home after cleaning, the smoke odor steps in our library cover the next level, including why ozone machines are risky.

Clean the Air You Breathe

While smoke is in the area, the goal is to keep outdoor air out and clean the air that is already inside.

• Close windows and doors. Set the air conditioner or car to recirculate.
• Use a MERV 13 filter in the furnace or air handler if your system can handle it, and run the fan continuously. Check the filter often, since it loads up fast during smoke events.
• Run a HEPA air purifier in the bedroom, and keep that door closed to create one cleaner room.
• A box fan with a MERV 13 furnace filter taped to the back is a well known low cost stand-in for a purifier. Tape it so air cannot bypass the filter and never leave it running unattended.
• Avoid anything that makes indoor pollution, such as frying, candles, gas stoves without a hood fan, and vacuuming with a non HEPA vacuum.

Swamp coolers, also called evaporative coolers, pull outdoor air in. Turn them off during heavy smoke if you can stay cool another way, or use a filter pad if the unit accepts one.

Pools, Cars, Roofs and Gutters

Pools. Skim ash off the surface, run the filter longer than usual, and backwash or clean the filter more often. Test and balance the water before anyone swims. Ash can push the pH up and cloud the water.

Cars. Do not wipe ash off a dry car, because it scratches the paint. Rinse it off with plenty of water at a car wash or with a hose, and change the cabin air filter if smoke was heavy.

Roofs and gutters. Ash and burned leaves in gutters can wash off in the first rain. Hose ash off low roofs from the ground if you can do it safely. Do not climb onto a roof covered in slippery ash. Clear gutters before the rainy season, because ash and debris can clog downspouts.

Solar panels. A layer of ash cuts output. Rinse them with a hose from the ground or hire a panel cleaner. Do not walk on panels.

If Your Home or a Neighbor’s Home Burned

The ash and debris where a structure burned is a different material. It can contain asbestos from older building materials, lead from paint, and metals and chemicals from electronics, batteries and cars. Do not sift, sweep or haul it on your own without guidance.

• After large fires, officials usually remove household hazardous waste such as batteries, propane tanks, paint and pool chemicals first, then debris is removed through a government program or licensed contractors.
• If you are allowed on your lot to look for valuables, wear a P100 respirator, gloves, goggles, long sleeves, pants and boots. Wet the area first, dig gently, and bag your clothes afterward.
• Do not let children or pets onto the lot.
• If your home survived but a neighbor’s burned, expect heavier ash and soot. Indoor cleaning, ducts and insulation may need a professional.

Keep receipts for respirators, cleaning supplies, air purifiers and hotel stays. Many homeowners policies cover smoke and ash cleaning even when the fire never touched the house.

Step by Step

1. Wait for Better Air

   Hold off on outdoor cleanup until the fire is contained and the air quality index is below 150. Stay inside with windows closed until then.

2. Suit Up

   Put on a fitted N95 or P100 respirator, goggles, gloves, long sleeves, long pants and closed shoes. Keep kids and pets inside.

3. Mist the Ash

   Lightly spray the ash with a hose on a shower setting or a pump sprayer so it is damp but not running.

4. Scoop and Bag

   Gently sweep damp ash into piles with a soft broom or scoop it with a flat shovel. Double bag it and put it in the trash unless officials say otherwise.

5. Keep It Out of Drains

   Use as little water as you can and block ash from washing into the street or storm drains.

6. HEPA Vacuum Inside

   Vacuum floors, rugs, furniture and sills slowly with a true HEPA vacuum. Then damp wipe hard surfaces with mild detergent.

7. Wash Fabrics

   Wash bedding, curtains and throws. Wash your cleanup clothes separately right after you finish.

8. Change Filters

   Replace the HVAC filter with a MERV 13 if your system allows, run a HEPA purifier, and change the car cabin filter if smoke was heavy.

9. Check the Pool and Garden

   Skim and filter the pool and test the water before swimming. Wash produce well and peel root vegetables.

Mistakes That Make It Worse

• Using a leaf blower on ash. It turns settled ash into a fine cloud you and your neighbors breathe.
• Dry sweeping with a stiff broom. Always mist ash first so it stays put.
• Wearing a cloth or paper dust mask. Only a fitted N95 or P100 respirator filters fine ash.
• Hosing ash into the street. It flows into storm drains and then creeks and the ocean.
• Vacuuming with a regular or shop vacuum. Without a HEPA filter it spreads the smallest particles indoors.

Where You Live Matters