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Lead Dust Testing Outside?

Lead Testing using XRF Gun

Dust Settling on Outside Patio or Furniture?

I was sitting on my porch in San Francisco watching kids play on the wooden deck and started to wonder, “is the dust on my porch contaminated with lead dust? If so, how best to clean it up?” So I did a little experiment and tested for lead dust before and after three different cleaning scenarios. This quick experiment demonstrated there is good reason behind the EPA’s recommended lead cleaning protocols.

Lead Dust Outside Furniture

How much lead is too much?

The U.S. government defines lead based paint (LBP) as, “any paint or surface coating that contains lead equal to or exceeding 1.0 mg/cm2 or 0.5% by weight.”

Lead Testing using XRF Gun

Lead paint testing using XRF analyzer

The exterior of my 1890’s earthquake cottage in San Francisco is covered in lead-based paint (LBP.) You

Lead Paint Testing using XRF analyzer

Lead paint testing using XRF analyzer

can see my exterior paint has a high lead content as measured by my XRF analyzer with a reading of 15 mg/cm2. XRF, X-ray fluorescence, is a non-destructive technique used to find how much lead is in paint. We recently bought a new XRF gun for Healthy Building Science and I love this lead testing gadget! It is a great way to quickly screen for lead paint in a building.

The exterior paint on my home is in pretty good condition (no paint chips), but I was curious to see if there was a lead dust hazard on the wood of my back deck. If the wood is contaminated with lead, what is the best way to clean it up?


Spoiler alert: Yes, I found high levels of lead dust. The way to clean it up is to HEPA (High Efficiency Particulate Air) vacuum, wet wipe with detergent, repeat HEPA vacuum and wet wipe. The moral of the story is two-fold: 1st) no dust, no lead dust hazard; 2nd) if lead dust, follow EPA’s lead cleaning recommendations, they work.

Summary of EPA Lead Abatement Protocol

Lead Testing Dust Wipes

Lead Testing Dust Wipes

The EPA recommends a combination of HEPA vacuuming followed by wet wiping with detergent, then repeating.

Does this combination really work? I decided to test this for myself. I took four dust wipe samples from my back deck:

1: control (no action taken)

2: HEPA vacuum only

3: HEPA vacuum and wet wipe

4: HEPA vacuum and wet wipe repeat HEPA vacuum and wet wipe


Lead Dust Cleaning Study Results

The results undeniably prove the technique works! No lead was detected after the final complete round of HEPA vacuum, wet wipe and repeat HEPA vacuum, wet wipe.


Sample Id Results in microgram per square foot
1 Control 1200 μg/ft²
2 HEPA 96 μg/ft²
3 HEPA vacuum and wet wipe 14μg/ft²
4 HEPA vacuum and wet wipe repeat HEPA vacuum and wet wipe >10 μg/ft² Undetected!

This demonstrates the importance of a) regular inspections by those familiar with environmental hazards, and b) regular deep cleaning. Just like your car or teeth, consider a regularly scheduled maintenance service for your home and office. The combination of inspections, testing and regular maintenance is effective at identifying problems early and minimizing risks.

EPA Recommendations for Controlling Lead Hazards

Here is more EPA information about protecting people from lead hazards:

  • Wash children’s hands, bottles, pacifiers, and toys often.
  • Make sure children eat nutritious meals high in iron and calcium. Children with good diets absorb less lead.
  • Remove shoes at the door or wipe soil off shoes before entering your house.
  • Run water for 15 to 30 seconds before drinking it, especially if you have not used your water for a few hours. Call your local health department or water supplier to find out about testing your water, or visit for EPA’s lead in drinking water information.
  • Cleaning: Vacuum then wet dust; if you dust then vacuum with a non HEPA vacuum you spread dust (and possibly lead) all over the house.
  • Your pediatrician can check for lead with a simple blood test. Children’s blood lead levels tend to increase rapidly from 6 to 12 months of age, tending to peak at 18 to 24 months of age. A simple blood test can detect lead. Blood lead tests are usually recommended for children at ages 1 & 2 and children or other family members who have been exposed to high levels of lead.
  • If you rent, notify your landlord of peeling or chipping paint.
  • Keep painted surfaces clean and free of dust. Clean floors, window frames, window sills, and other surfaces weekly. Use a mop or sponge with warm water and a general all-purpose cleaner. *Remember: never mix ammonia and bleach products together because they form chloramine, a dangerous gas.
  • Carefully clean up paint chips immediately without creating dust.
  • Thoroughly rinse sponges and mop heads often during cleaning of dirty or dusty areas, and again afterward.
  • Wash your hands and your children’s hands often, especially before they eat and before nap time or bedtime.
  • Keep play areas clean. Wash bottles, pacifiers, toys, and stuffed animals regularly.
  • Keep children from chewing window sills, other painted surfaces, or eating soil.
  • When renovating, repairing, or painting, hire only EPA or state approved Lead-Safe Certified renovation firms.

To learn more about EPA’s requirements for RRP projects visit their Get Lead Safe page, or read The Lead-Safe Certified Guide to Renovate Right.

If you have concerns about lead in or around your building or want lead dust testing, please complete this form and HBS can send you an estimate to provide lead inspecting and lead testing services for the San Francisco Bay Area.

Written by Anne-Lise Breuning.

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