Of the 254 compounds in the Embr Exposure Ledger, 122 have been measured in the general population by national biomonitoring — US NHANES or Canada’s CHMS. Of those, 78 have no inhalation reference concentration and no residential indoor-air screening level published by EPA.
36 of the 78 do have an oral reference dose. That is the part worth sitting with: the toxicology exists, but for eating and drinking. The gap is not that these compounds are unstudied. It is that the route by which a bedroom would deliver them — air, for eight hours a night — has no number attached. The remaining 42 do not appear in EPA’s consolidated table under the name the Atlas uses.
What this is not
This is not a ranking of danger, and the distinction is the whole point of publishing it.
The best-known list of this shape is the EWG Dirty Dozen. Winter and Katz took the same USDA data it was built on, ran an actual exposure assessment, and concluded the methodology was “insufficient to allow any meaningful rankings among commodities” because it ranked presence without dose-response (J Toxicol 2011). A 2009 survey of Society of Toxicology members found 79% thought EWG overstates chemical risk. That critique is correct, and it is the reason this list ranks something else.
The Dose Gap ranks the missing dose-response itself. Every entry is a statement about the state of the evidence, not about the compound. A missing reference value is not evidence of safety and it is not evidence of harm. It means no agency has published a number for that route, so nobody — including us — can tell you whether a measured bedroom concentration would matter.
Method
Every compound in the Ledger carrying a body-burden record from NHANES or CHMS, which has neither an inhalation RfC nor a residential indoor-air screening level in the EPA Regional Screening Level Summary Table (which consolidates IRIS, PPRTV, ATSDR, Cal EPA and OPP). Ordered by how many independent presence datasets carry the compound, because breadth of presence evidence is what makes an absent dose benchmark consequential.
Derived from Embr Exposure Ledger v1.3, built 2026-07-22. The ranking is downloadable as JSON under CC BY 4.0. It is our own arithmetic on published federal data, not a figure from any paper, and it is reproducible from the linked dataset.
One caveat we would rather state than have found. Some entries are absent from EPA’s table because of chemical speciation rather than genuine absence. EPA lists Chromium(VI) and Chromium(III) separately, while the Atlas carries a generic chromium page, so “not in EPA’s table” there means “not under this name.” Those entries are marked as such rather than counted as if no toxicology existed.
The 78 compounds
| Compound | Presence datasets | Measured in | Reference value status |
|---|---|---|---|
| Chlordane | 4 | — | not in EPA’s table under this name |
| Chromium | 4 | blood | not in EPA’s table under this name |
| Fluoranthene | 4 | — | oral only — RfD 0.04 mg/kg-day (EPA IRIS) |
| Fluorene | 4 | Urine | oral only — RfD 0.04 mg/kg-day (EPA IRIS) |
| GenX (HFPO-DA) | 4 | serum | oral only — RfD 3e-06 mg/kg-day |
| Perfluorobutane sulfonate | 4 | serum | oral only — RfD 0.0003 mg/kg-day (EPA PPRTV) |
| Perfluorodecanoic acid | 4 | serum | oral only — RfD 2e-09 mg/kg-day (EPA IRIS) |
| Perfluorohexane sulfonate | 4 | serum | oral only — RfD 2e-05 mg/kg-day (ATSDR) |
| Perfluorononanoic acid | 4 | serum | oral only — RfD 3e-06 mg/kg-day (ATSDR) |
| Perfluorooctane sulfonate | 4 | serum | oral only — RfD 1e-07 mg/kg-day |
| Perfluorooctanoic acid | 4 | serum | oral only — RfD 3e-08 mg/kg-day |
| Phenanthrene | 4 | Urine | not in EPA’s table under this name |
| Pyrene | 4 | Urine | oral only — RfD 0.03 mg/kg-day (EPA IRIS) |
| 4-tert-Octylphenol | 3 | urine | not in EPA’s table under this name |
| Atrazine | 3 | urine | oral only — RfD 0.003 mg/kg-day (ATSDR) |
| Benzyl butyl phthalate | 3 | Urine | oral only — RfD 0.2 mg/kg-day (EPA IRIS) |
| Bisphenol A | 3 | urine | oral only — RfD 0.05 mg/kg-day (EPA IRIS) |
| Copper | 3 | serum | oral only — RfD 0.04 mg/kg-day (HEAST) |
| Di-n-octyl phthalate | 3 | — | oral only — RfD 0.01 mg/kg-day (EPA PPRTV) |
| Dibutyl phthalate | 3 | Urine | oral only — RfD 0.1 mg/kg-day (EPA IRIS) |
| Nicotine | 3 | urine | not in EPA’s table under this name |
| Nitrate | 3 | urine | oral only — RfD 1.6 mg/kg-day (EPA IRIS) |
| Perfluorobutanoic acid | 3 | urine | oral only — RfD 0.001 mg/kg-day (EPA IRIS) |
| Perfluoroheptanoic acid | 3 | serum | not in EPA’s table under this name |
| Perfluorohexanoic acid | 3 | serum | oral only — RfD 0.0005 mg/kg-day (EPA IRIS) |
| Propoxur (Baygon) | 3 | — | oral only — RfD 0.004 mg/kg-day (EPA IRIS) |
| Short-chain chlorinated paraffins | 3 | — | not in EPA’s table under this name |
| Silver nanoparticles | 3 | — | oral only — RfD 0.005 mg/kg-day (EPA IRIS) |
| TDCPP (chlorinated tris) | 3 | — | oral only — RfD 0.02 mg/kg-day (ATSDR) |
| 2,4-Dichlorophenoxyacetic acid | 2 | urine | oral only — RfD 0.01 mg/kg-day (EPA IRIS) |
| Alpha-pinene | 2 | — | not in EPA’s table under this name |
| Bis(2-ethylhexyl) tetrabromophthalate | 2 | — | not in EPA’s table under this name |
| Bisphenol AF | 2 | — | not in EPA’s table under this name |
| Bisphenol S | 2 | — | not in EPA’s table under this name |
| Butylparaben | 2 | urine | not in EPA’s table under this name |
| Chlorpyrifos | 2 | Urine | oral only — RfD 0.001 mg/kg-day (ATSDR) |
| Cotinine | 2 | serum | not in EPA’s table under this name |
| Decanal | 2 | serum | not in EPA’s table under this name |
| Diazinon | 2 | — | oral only — RfD 0.0007 mg/kg-day (ATSDR) |
| Diethyl phthalate | 2 | Urine | oral only — RfD 0.8 mg/kg-day (EPA IRIS) |
| Diisobutyl phthalate | 2 | — | not in EPA’s table under this name |
| Diisodecyl phthalate | 2 | — | not in EPA’s table under this name |
| Diisononyl phthalate | 2 | Urine | not in EPA’s table under this name |
| Dimethyl phthalate | 2 | Urine | not in EPA’s table under this name |
| Endrin | 2 | serum | oral only — RfD 0.0003 mg/kg-day (EPA IRIS) |
| Galaxolide (HHCB) | 2 | — | not in EPA’s table under this name |
| Glyphosate | 2 | urine | oral only — RfD 0.1 mg/kg-day (EPA IRIS) |
| Hexanal | 2 | serum | not in EPA’s table under this name |
| Lithium | 2 | — | oral only — RfD 0.002 mg/kg-day (EPA PPRTV) |
| Methylparaben | 2 | urine | not in EPA’s table under this name |
| N-Nitrosonornicotine | 2 | urine | not in EPA’s table under this name |
| Nonanal (Aldehyde C-9) | 2 | serum | not in EPA’s table under this name |
| Octanal | 2 | serum | not in EPA’s table under this name |
| p-Phenylenediamine | 2 | — | oral only — RfD 0.001 mg/kg-day (PPRTV appendix) |
| Perfluoropentanoic acid | 2 | urine | not in EPA’s table under this name |
| Triphenyl phosphate | 2 | — | not in EPA’s table under this name |
| Tris(2-chloroethyl) phosphate (TCEP) | 2 | — | oral only — RfD 0.007 mg/kg-day (EPA PPRTV) |
| 1-Hydroxypyrene | 1 | urine | not in EPA’s table under this name |
| 2-Ethylhexyl-2,3,4,5-tetrabromobenzoate | 1 | — | not in EPA’s table under this name |
| 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol | 1 | urine | not in EPA’s table under this name |
| Bisphenol F | 1 | — | not in EPA’s table under this name |
| DEET (N,N-Diethyl-meta-toluamide) | 1 | urine | not in EPA’s table under this name |
| Deltamethrin | 1 | — | not in EPA’s table under this name |
| Ethylparaben | 1 | urine | not in EPA’s table under this name |
| Imidacloprid | 1 | urine | not in EPA’s table under this name |
| Mono(2-ethylhexyl) phthalate | 1 | urine | not in EPA’s table under this name |
| Oxybenzone (Benzophenone-3) | 1 | urine | not in EPA’s table under this name |
| Pentabromodiphenyl ether | 1 | — | oral only — RfD 0.0001 mg/kg-day (EPA IRIS) |
| Pentabromodiphenyl ether (BDE-100) | 1 | serum | not in EPA’s table under this name |
| Perfluorooctanesulfonamide | 1 | serum | not in EPA’s table under this name |
| Propylparaben | 1 | urine | not in EPA’s table under this name |
| Tetrabromodiphenyl ether | 1 | serum | oral only — RfD 0.0001 mg/kg-day (EPA IRIS) |
| Tributyl phosphate | 1 | — | oral only — RfD 0.01 mg/kg-day (EPA PPRTV) |
| Triclocarban | 1 | urine | not in EPA’s table under this name |
| Triclosan | 1 | urine | not in EPA’s table under this name |
| Tricresyl phosphate (TCP) | 1 | — | oral only — RfD 0.02 mg/kg-day (ATSDR) |
| Tris(2-butoxyethyl) phosphate | 1 | — | not in EPA’s table under this name |
| Tris(chloroisopropyl) phosphate | 1 | — | oral only — RfD 0.01 mg/kg-day (PPRTV appendix) |
Citing this
Eyjolfson, K. (2026). The Dose Gap 2026.
Embr Sleep. https://embrsleep.com/pages/dose-gap
Derived from Embr Exposure Ledger v1.3. Built 2026-07-22.Reusable with attribution under CC BY 4.0. If you are a researcher and one of these gaps is yours to close, we would like to hear about it — get in touch.