What happened.
A homeowner in an old Nashville house, built in 1925, hired a handyman to deal with a painted porch ceiling. Instead of leaving it alone or sealing it, the guy took a sander to the whole thing with almost no containment. Lead paint dust everywhere. There is a four-year-old in the house.
Then, trying to clean up his own mess, he loaded a pressure washer with muriatic acid, which is just a hardware-store grade of hydrochloric acid at roughly 30 percent, and sprayed down the porch. The old ceiling is not one coat. It is several layers of old lead paint (orange, blue, white) with some newer non-lead paint on top from a later owner.




What the test showed.
He sprayed Fluoro-Spec and put the light on it. This was not one stray speck in a corner. The entire ceiling under the beam lights up green. His words: it looks radioactive, like a Simpsons episode. It even glows through the fresh white primer, because the sanding dust got mixed right into that top coat.
I shine the light on it and the whole area under the beam is just glowing. I have a HEPA vac and I tried the D-Lead solutions. Nothing really touched it.
Why washing lead with acid is the worst move.
This is the part almost nobody knows, and it is why the "cleanup" backfired. Hydrochloric acid reacts with lead to form lead chloride, which is semi-soluble. In this context, soluble is close to the same thing as bioavailable, meaning a form the body can actually absorb.
So spraying acid on lead paint dust did not remove it. It converted it into a form that is easier for a child's body to take up, not harder. The guy trying to fix the problem made it more dangerous, and there is no way to see that with your eyes.
The fix is a box of TSP.
Trisodium phosphate. It is a cheap powder you mix with water and mop or wash the area down with. The phosphorus in it binds the lead into lead phosphate, which will not dissolve. Phosphate holds onto lead more tightly than hydrochloric acid does, so it undoes the acid problem and then keeps going.
Mix the powder into a bucket of water, wash the whole area, and most of the glow drops out because the lead is now locked up. It is a base, so it also neutralizes the leftover acid on its own. TSP is caustic (a little like lye, it will make your fingers feel slippery), so gloves and eye protection, but it rinses away and it is genuinely a good cleaner on top of the chemistry.
Why "not absorbed" beats "not there."
The body absorbs lead by accident. It comes in through the same channels in your gut that are meant to pull in iron and calcium. Bind that lead to phosphate and those channels no longer recognize it, so it is not taken up. It passes through instead.
That is the whole point, and it is why you do not have to strip every last microgram to make a real dent. Even if some lead stays on the surface, once it is lead phosphate the fraction your body can actually absorb drops way down. The EPA tends to wave people off TSP, but that is because phosphate running into waterways feeds algae blooms, a water-supply concern, not a sign it does not work on your porch.
Painted over is not gone, but it is stuck.
The lead fluoresced right through the fresh white primer, so a coat of paint does not make it disappear. The upside: that loose dust is now trapped in the first layer of paint instead of floating around. Re-coating on top should keep it from working its way up through new paint. The plan here is TSP wash first, then encapsulate, and keep the kid off the soil near the foundation until it is checked.
What the samples showed.
The homeowner mailed in paint chips and soil in labeled zip bags, and they went straight on the XRF (that is a scan, a different thing from the spray test). These are first-pass screening counts taken right through the bags. Longer counts are coming, but the picture is already clear. Numbers are parts per million.
| Sample | Lead (ppm) | What else showed |
|---|---|---|
| Door frame, painted face | 929 | Titanium and zinc from newer white topcoats |
| Door frame, back of the same piece | 4,099 | Arsenic 711. The buried layers run hotter than the face. |
| Exterior paint sample | 174,984 | 17.5% lead by weight. Arsenic 10,002. Zinc 117,315. The worst thing on the bench. |
| Porch ceiling (the sanded one) | 29,534 | About 3% lead. No chromium, so no lead chromate. Titanium and zinc are the newer whites on top. |
| The blue-green chips | 16,279 | Arsenic 693. No chromium, no cadmium. The lead is the white lead in and under the color, not the color itself. |
| Play-area soil | 41 | Normal background dirt. A tenth of the EPA trigger for bare play-area soil (400). |
| Side-yard soil, by the house | 1,772–9,583 | Loose mix 1,772. A paint chunk in it hit 9,583, another spot 6,862. Genuinely contaminated. |




The cadmium worry, answered: no cadmium showed above detection on any sample, and no chromium either. So the color coats are not lead chromate and not a cadmium pigment. And the acid could not have added either one, because acid cannot add an element that was never there. It can only change the form of what is. That is exactly why the TSP wash matters: phosphate outcompetes chloride and locks the lead back down, whether or not acid got there first.
The soil tells the practical story. The dirt out by the play area came back at background levels, so that part of the yard is fine. The strip along the side of the house is another matter: paint has been shedding into that ground for decades, long before the sander showed up. The fix there is not panic, it is coverage. Mulch, sod, or hardscape over it, and the kid stays off the bare strip in the meantime.
Samples arrived and the first-pass XRF numbers are up above. Porch plan: TSP wash, then encapsulation. The side strip gets covered, and the play area came back clean. Longer scan counts and the after-glow post here next.
Old house, kids, and a paint project you are not sure about?
The kit is the whole toolkit, not just a test strip. Spray, shine the light, and see the lead before anyone sands anything.
Get a Fluoro-Spec kit →Would you have made the same mistake?
3 quick questions on what actually helps (and what makes lead worse) in an old house.