Statistics Canada has been measuring environmental chemicals in Canadians' blood and urine since 2007. We matched its chemical index to the Bedroom Chemistry Atlas by CAS number. Forty-three of the compounds we write about are detectable in 90% or more of the Canadians tested. Thirteen were found in everyone. Three of them are flame retardants of the kind used in furniture and mattresses.
That sentence is easy to misread, so here is the boring version first: detectable is not the same as dangerous, and it is not a dose. The rest of this piece is mostly about that distinction, because it is the part almost every write-up of biomonitoring data gets wrong.
What "detectable" actually means
A detection frequency is the share of people whose sample contained more of a chemical than the laboratory could reliably measure. That threshold is called the limit of detection, and it is a property of the instrument, not of the person. Regulatory — Health Canada, Canadian Health Measures Survey.
The consequence is counterintuitive. When a lab upgrades its equipment and can measure lower concentrations, detection frequencies rise, and nobody's exposure has changed. This is not hypothetical. Canada's survey did not detect short-chain PFAS in serum until its fifth cycle, and the researchers noted the jump was explained in part by lower detection limits rather than by rising exposure. Peer-reviewed — Frontiers in Public Health, 2024.
So "100% of Canadians have detectable lead" is true, and it means the instruments are good. It does not mean every Canadian is lead-poisoned. Levels of lead, cadmium and mercury in Canadians have each fallen by more than 30% since the survey began. Regulatory — Statistics Canada.
The part that surprised us
We did not build this join looking for flame retardants. They turned up anyway.
TDCPP, TCEP and TPHP are the three organophosphate flame retardants that appear most often in our own reporting on why mattresses contain flame retardants and on what flame-retardant-free actually means. All three are detectable in more than nine of ten Canadians, measured through their urinary breakdown products rather than the parent chemical.
TCEP, a flame retardant restricted in children's products, was measurable in 91.1% of the 2,345 Canadians tested in 2023–2024. Regulatory — Canadian Health Measures Survey, Cycle 7.
We have written about TDCPP and TCEP as things that are in objects. The survey measures them as things that are in people. Those are the same compounds, and until we ran this join we had never put the two facts on the same page.
The 43 compounds
Ranked by detection frequency. Every row matched on CAS number, not on name, so none of these is a guess about which chemical is which. The year column matters more than it looks: it is the most recent cycle in which that specific chemical was measured, and it ranges from 2007 to 2024.
| Compound | Detected in | Measured | Sample | What was measured |
|---|---|---|---|---|
| Acrylamide | 100.0% | 2018–2019 | 10,094 | acrylamide haemoglobin adduct |
| Arsenic | 100.0% | 2023–2024 | 14,251 | arsenic (total) |
| Benzene | 100.0% | 2014–2015 | 7,529 | trans,trans-muconic acid (t,t-MA) |
| Cobalt | 100.0% | 2009–2011 | 6,070 | cobalt |
| Copper | 100.0% | 2009–2011 | 11,388 | copper |
| Di(2-ethylhexyl) phthalate | 100.0% | 2018–2019 | 11,041 | mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) |
| Fluorene | 100.0% | 2014–2015 | 7,548 | 2-hydroxyfluorene |
| Lead | 100.0% | 2023–2024 | 35,571 | lead |
| Manganese | 100.0% | 2023–2024 | 15,412 | manganese |
| Naphthalene | 100.0% | 2014–2015 | 7,490 | 2-hydroxynaphthalene |
| Nickel | 100.0% | 2016–2017 | 1,207 | nickel |
| Phenanthrene | 100.0% | 2014–2015 | 7,533 | 1-hydroxyphenanthrene |
| Selenium | 100.0% | 2023–2024 | 24,535 | selenium |
| Nicotine | 99.9% | 2018–2019 | 492 | cotinine (smokers) |
| Pyrene | 99.9% | 2014–2015 | 7,241 | 1-hydroxypyrene |
| Oxybenzone (Benzophenone-3) | 99.8% | 2018–2019 | 2,397 | oxybenzone (benzophenone-3 [BP-3]) |
| Bisphenol A | 99.7% | 2023–2024 | 24,909 | bisphenol A (BPA) |
| Dibutyl phthalate | 99.7% | 2018–2019 | 11,006 | mono-n-butyl phthalate (MnBP) |
| DDT (dichlorodiphenyltrichloroethane) | 99.7% | 2007–2009 | 1,668 | p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) |
| Chromium | 99.6% | 2016–2017 | 1,207 | chromium |
| Perfluorohexane sulfonate | 99.6% | 2018–2019 | 9,510 | perfluorohexane sulfonic acid (PFHxS) |
| Diethyl phthalate | 99.4% | 2018–2019 | 11,034 | mono-ethyl phthalate (MEP) |
| Fluoride | 99.4% | 2023–2024 | 16,410 | fluoride |
| Perfluorooctane sulfonate | 99.3% | 2018–2019 | 9,512 | perfluorooctane sulfonic acid (PFOS) |
| Toluene | 99.2% | 2016–2017 | 7,391 | toluene |
| Barium | 98.9% | 2016–2017 | 1,209 | barium |
| Diisobutyl phthalate | 98.9% | 2018–2019 | 7,775 | mono-isobutyl phthalate (MIBP) |
| Perfluorononanoic acid | 98.5% | 2018–2019 | 6,362 | perfluorononanoic acid (PFNA) |
| Benzyl butyl phthalate | 98.3% | 2018–2019 | 11,024 | mono-benzyl phthalate (MBzP) |
| Xylenes (o-, m-, p-) | 98.2% | 2016–2017 | 7,407 | m-xylene and p-xylene |
| Mercury | 97.5% | 2016–2017 | 1,209 | mercury (total) |
| Chlordane | 97.2% | 2007–2009 | 1,668 | oxychlordane |
| Triphenyl phosphate | 96.5% | 2018–2019 | 2,399 | diphenyl phosphate (DPHP) |
| Bisphenol S | 96.2% | 2023–2024 | 11,065 | bisphenol S (BPS) |
| TDCPP (chlorinated tris) | 95.2% | 2018–2019 | 2,398 | bis(1,3-dichloro-2-propyl) phosphate (BDCPP) |
| Uranium | 95.0% | 2016–2017 | 1,207 | uranium |
| Chlorpyrifos | 94.9% | 2016–2017 | 6,700 | 3,5,6-trichloro-2-pyridinol (TCPy) |
| Diisodecyl phthalate | 93.8% | 2018–2019 | 4,784 | monocarboxyisononyl phthalate (MCINP) |
| Dimethyl phthalate | 93.2% | 2018–2019 | 10,933 | mono-methyl phthalate (MMP) |
| Silver nanoparticles | 92.3% | 2016–2017 | 1,208 | silver |
| Cadmium | 92.0% | 2023–2024 | 35,570 | cadmium |
| Tris(2-chloroethyl) phosphate (TCEP) | 91.1% | 2023–2024 | 2,345 | bis-2-(chloroethyl) phosphate (BCEP) |
| Galaxolide (HHCB) | 90.6% | 2023–2024 | 2,445 | galaxolide (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[g]-2-benzopyran [HHCB]) |
What Canada has stopped measuring
Only 10 of the 43 were measured in the most recent cycle. The other 33 carry older dates, some as far back as 2007–2009.
Benzene is the clearest case. It shows a 100% detection frequency across 7,529 people, and that figure is from 2014–2015. Whatever is true of benzene in Canadians today, this survey has not looked in roughly a decade.
That is not a criticism of the survey, which rotates chemicals in and out by design and cannot measure everything every cycle. It is a caution about the number. A detection frequency with a 2014 date describes 2014.
What this does not establish
It does not establish harm. Detection frequency carries no information about dose, and none of these figures should be read as a health finding for any individual.
It does not establish a source. That DEHP is measurable in effectively everyone says nothing about where any particular person's DEHP came from. Phthalates are in food packaging, personal care products, vinyl flooring and building materials as well as in mattresses.
It does not establish a trend. Comparing one cycle's detection frequency against another's is unreliable when detection limits changed between them, which they often did.
What it does establish is narrower and still worth saying: the compounds documented in this Atlas are not theoretical. They are present, measurably, in the large majority of a national sample.
How we built this
Statistics Canada publishes a chemical index for its biomonitoring dashboard listing 337 measured chemicals with CAS numbers for both the parent compound and the biomarker actually measured. We joined that index to the Atlas through our shared compound resolver, matching on CAS first. 91 of the 337 matched a compound we document; 43 of those cleared 90% detection.
Biomonitoring rarely measures the chemical itself. It measures a metabolite, which is what the body converts it into. DEHP is tracked through MEHHP, TCEP through BCEP. The "what was measured" column above names the actual biomarker for each row so the chain is visible.
The full joined dataset is published in the Embr Exposure Ledger, which is downloadable and free to reuse with attribution.
Frequently asked questions
Does a 100% detection rate mean the chemical is harmful?
No. Detection frequency measures how often a chemical is present above the laboratory's limit of detection. It carries no information about dose, and no information about whether that amount causes harm. A more sensitive instrument raises detection frequency without any change in exposure.
Are flame retardants from mattresses really found in people?
Three organophosphate flame retardants used in furniture and some mattresses (TDCPP, TCEP and TPHP) are detectable in more than 90% of Canadians tested. The survey cannot say where any individual's exposure came from, because these compounds are used in furniture, electronics and building materials as well as mattresses.
How current is this data?
It varies by chemical. Ten of the 43 compounds were measured in the 2023–2024 cycle. The rest carry earlier dates ranging back to 2007–2009, because the survey rotates which chemicals it measures each cycle. Each row in the table shows its own measurement year.
Is this Canadian data relevant outside Canada?
Partly. The United States runs an equivalent survey, NHANES, and many of the same compounds appear in both. Directly comparing levels between the two is unreliable, because the surveys use different laboratories, detection limits, sample matrices and years.
What is a biomarker?
The substance actually measured in blood or urine. The body converts most chemicals before excreting them, so surveys measure the breakdown product. DEHP is measured as MEHHP; TCEP is measured as BCEP.
Related reading: we joined EPA production volumes to CDC biomonitoring for 43 chemicals and found that how much America makes of something barely predicts whether it shows up in blood.
- Canadian Health Measures Survey: human biomonitoring of environmental chemicals — Regulatory
- Canadian Biomonitoring Dashboard, Health Canada — Regulatory
- A closer look at declining levels of three toxic metals in the Canadian population, Statistics Canada — Regulatory
- Management of phthalates in Canada and beyond, Frontiers in Public Health, 2024 — Peer-reviewed