Dust is the form of lead that actually reaches children. The recognized swab kits were never built or tested to find it. FluoroSpec was.
A fair question comes up whenever lead test kits are bought for the public: why not just use the "EPA approved" ones? This briefing answers it, with every claim sourced. It turns on one thing: what an "EPA recognized" kit is actually recognized to do, and whether that has anything to say about finding lead hazards in occupied homes.
One question is worth asking: what is an "EPA recognized" swab actually recognized to do?
Recognition covers two narrow things, and only those:
The term itself is "recognized for use under RRP." Putting test kits in residents' hands, in occupied homes with no renovation underway, is not the situation that recognition speaks to. The recognized swabs were not built or tested to find lead-based paint dust, the exposure that reaches children. There is no "EPA approved" category for any lead test kit.
The sourced detail behind each point above.
A lead test kit "recognized for use under the RRP Rule" is one a certified renovator may use, on specific substrates, to confirm regulated lead-based paint is not present on a component, so lead-safe work practices can be skipped for that component.
"EPA recognizes lead test kits for use in complying with the negative response criterion of the RRP Rule. To date no lead test kit has met both of the performance criteria outlined in the RRP rule."U.S. EPA. What lead test kits are recognized by EPA?
Stated plainly:
RRP recognition is about safe contractor work. It is not about finding hazards, and it is not about people who are not having renovation work done.
Federal definition: paint is lead-based when it contains lead at or above 1.0 mg/cm², or 0.5% by weight (5,000 ppm), in housing built before 1978 and in child-occupied facilities.
EPA's recognition protocol has two parts: a negative-response criterion and a positive-response criterion. No kit has ever met the positive-response criterion. Under the current protocol a chemical kit cannot be recognized to determine that lead is present, because of the false-positive rate. That is the reason a recognized kit can only determine lead-based paint is not present.
"Based on the ETV results, there are no kits that have met both the negative response and positive response criteria requirements; however, there is one kit that met only the negative response criterion."U.S. EPA. Lead Test Kits, ETV results
Sources: EPA Lead Test Kits, What kits are recognized, EPA ETV evaluation.
FluoroSpec is a fluorescence test, not a color-change test. The reagent (isopropyl alcohol CAS 67-63-0 at ≥97.25%, methylammonium bromide CAS 6876-37-5 at 1.5%, mandelic acid CAS 90-64-2 at 1.25%) forms microscopic methylammonium lead bromide crystals on contact with lead. Those crystals emit green light under 365 nm UV.
The crystals act like fluorescent mirrors, shining back the invisible UV light as visible green. The amount of lead tracks with the amount of light that comes off the surface.
FluoroSpec responds to exposed white-lead paint, leaded ceramics, metallic lead, lead debris, and lead-based paint dust. In our dust investigation, individual particles near 40 micrometers were made visible. The recognized swab kits were never built or tested for this. The clips below are the real result: a positive, glowing surface and a clean negative.
A surface can be lead-based paint and not currently a hazard. A surface can be a serious hazard with no paint ever identified. Hazards come from friction and impact surfaces (windows, doors, stairs, floors), chewable surfaces, and deteriorating paint. The route that poisons children is dust. Dust-hazard standards let a program act before a child's blood lead rises, not after.
The perovskite fluorescence method this test uses is peer-reviewed and published, with Eric Ritter as a co-author: van Geen A., Helmbrecht L., Ritter E., et al., "Lead-based paint detection using perovskite fluorescence and X-ray fluorescence," Analytica Chimica Acta 1307 (2024) 342618. Read the paper.
Across 76 paint samples, measured against portable XRF and laboratory ICP-AES, the methylammonium bromide perovskite reaction detected lead in paint down to about 400 ppm, with 95% sensitivity and 94% specificity at that threshold. That is an order of magnitude below the US lead-based-paint definition of 5,000 ppm, and it outperformed the rhodizonate swab. The study is candid about one limit: lead paint that has been painted over with low-lead paint will not respond to a surface test, though XRF still reads it through the layer.
Separately, a white paper by Eric Ritter, "Single-Particle Detection of Lead-Based Paint Dust via Field-Deployable Methylammonium Bromide Fluorescence Spectroscopy," looked at dust specifically. Individual lead-based paint dust particles at or above roughly 40 µm fluoresced visibly to the naked eye under 365 nm UV, with no false positives across the non-lead controls. Smaller particles were visible under magnification.
In practice the limit on intact paint is in the few-hundred-ppm range, which still captures lead paint from 1978 through roughly 2008, not only the oldest layers. What this method is strongest at is lead-based paint dust, the form that actually reaches children. Stated plainly so there are no surprises.
For the full sensitivity workup on real vintage paint, see the limit of detection page.
EPA authorized the manufacture of this chemical under a TSCA Section 5 Low Volume Exemption (40 CFR 723.50), non-transferable, case L-25-0206. Authorized volume is up to 180 kg per year, about 300,000 bottles.
This is EPA permission to make the chemical. It is separate from RRP. EPA does not approve test kits.
The methylammonium bromide reagent is manufactured under a Low Volume Exemption (LVE) under TSCA Section 5 (40 CFR 723.50), non-transferable. EPA case L-25-0206. EPA's term is "recognized," not "approved." There is no "EPA approved" category for these products.
Both links: EPA Status of Pre-Manufacture Notices (search case L-25-0206) and a copy of the EPA letter (PDF).
In residents' hands, this finds the hazard that actually poisons children: lead dust, where it is, and how bad it is. Occupants can see the severity, confirm a cleanup worked, and keep monitoring during interim controls instead of waiting on a lab. It moves a program toward primary prevention. It travels by word of mouth through a neighborhood.
It shows the source and the resulting dust together. That is direct evidence of a presumptive lead hazard, without waiting on a lab.
People act on what they can see. A surface that lights up green is harder for an occupant or a landlord to dismiss than a number on a report.
It shows exactly where the lead dust is, so an occupant can see the problem and target the cleanup instead of guessing.
Clean from cleanest to dirtiest, re-check as you go, and concentrate effort where the dust actually is.
Re-test the area after cleaning to see whether the dust is actually gone, and keep checking during interim controls to confirm the hazard stays stopped.
In a public distribution, residents find and act on hazards in their own homes, before an elevated blood lead, and the information moves through the neighborhood.
Eric Ritter, Fluoro-Spec Inc. · eric@detectlead.com · 631-461-1838
six tools my family uses to keep our kid under the fda action threshold. type your email. you get all six on this page in two seconds.
i copied your email to the list. the first email lands in a couple minutes. open the pack below now.
bookmark this page. the database and the leaducational pages update almost every day. the bottle sheet and the dish list grow as the lab finishes new runs.
the information is free. the kit is for parents who, after reading the framework, decide they want to walk around the nursery with a drop bottle tonight. one drop of fluoro-spec on the painted side of a plate. if it's lead, it glows green in seconds. no lab.
see the drip kit, $50 →