At a glance
| Chemical family | Phthalate plasticizer — diisononyl phthalate, a high-molecular-weight branched-chain phthalate |
| CAS number | 28553-12-0 |
| Classification | IARC Group 2B — possibly carcinogenic to humans (July 2026); California Proposition 65 carcinogen (since Dec. 2013); CPSC-restricted in children's toys/child care articles (0.1% limit) |
| Where you encounter it | Flexible PVC generally: vinyl flooring, wall coverings, garden hoses, cables, automotive interiors — and a significant share of vinyl mattress covers, crib mattress laminate, and other children's sleep products |
| Sleep micro-environment relevance | A 2025 in-home study of 25 children's bedrooms found DiNP above the 0.1% toy-restriction threshold in 5 of the mattresses sampled — a level unregulated in mattresses even though it is banned in toys |
| Activated carbon capture | Partial — DiNP is a heavy, low-volatility SVOC that migrates into dust rather than off-gassing as a gas, so gas-phase carbon capture addresses only part of the exposure pathway |
Regulatory & certification status
Where DiNP (Diisononyl Phthalate) stands across the major regulatory systems and the certifications a bedroom product might carry. Each row links to the governing instrument; where a jurisdiction has no specific measure, that is stated plainly rather than left blank.
| International (IARC) | In July 2026, the IARC Monographs Working Group (Meeting 142, published in The Lancet Oncology on 3 July 2026) classified diisononyl phthalate as Group 2B — possibly carcinogenic to humans — alongside butyl benzyl phthalate and dibutyl phthalate. The basis: sufficient evidence of carcinogenicity in experimental animals, inadequate evidence in humans, and strong mechanistic evidence. This is a brand-new classification; prior to July 2026, DiNP had not been evaluated by IARC. Regulatory — IARC · The Lancet Oncology |
| United States | DiNP is listed under California Proposition 65 as a chemical known to cause cancer, effective 20 December 2013 (listed via the State's Qualified Experts mechanism), with an adopted No Significant Risk Level (NSRL) of 146 µg/day. Under TSCA, EPA finalized a risk evaluation for DiNP on 14 January 2025: EPA determined DiNP presents an unreasonable risk of injury to human health driven by certain worker conditions of use (high inhalation exposure from spray application of adhesives, sealants, paints and coatings), and did not identify unreasonable risk to consumers, the general population, or the environment. EPA must now develop risk-management measures for the identified worker risk. Separately, the CPSC permanently prohibits DiNP above 0.1% by weight in children's toys and child care articles under 16 CFR 1307.3(b) — a rule finalized in 2017 following a 2014 CPSC Chronic Hazard Advisory Panel (CHAP) recommendation that found DiNP antiandrogenic in animal studies, though less potent than other regulated phthalates. Regulatory — OEHHA · US EPA · CPSC / eCFR |
| European Union | DiNP is restricted under REACH Annex XVII entry 52: it must not be used at concentrations greater than 0.1% by mass of the plasticised material in toys and childcare articles that can be placed in the mouth by children. (Entry 52 covers DiNP, DIDP and DnOP; the all-toys entry 51 covers DEHP/DBP/BBP, not DiNP.) DiNP is NOT on the REACH Candidate List of Substances of Very High Concern and is not on the Authorisation List (Annex XIV) — it is restricted only under Annex XVII. It has no harmonised CLP classification in Annex VI: ECHA's Committee for Risk Assessment (RAC) adopted an opinion in 2018 concluding that classification for reproductive toxicity was not warranted, and a subsequent ECHA final review report on new scientific evidence found no basis to re-examine the existing entry-52 restriction. DiNP is not listed as an EU persistent organic pollutant. Note: this EU classification predates IARC's July 2026 Group 2B finding and has not yet been revisited in light of it. Regulatory — EUR-Lex · REACH Annex XVII consolidated |
| Canada | DiNP is restricted under the Phthalates Regulations (SOR/2016-188) made under the Canada Consumer Product Safety Act: vinyl in any part of a toy or child-care article that can reasonably be expected to be placed in the mouth of a child under four years of age must not contain more than 1,000 mg/kg (0.1%) DiNP. DiNP is NOT on Schedule 1 of CEPA (the List of Toxic Substances). Canada's final screening assessment of the Phthalate Substance Grouping (2020) concluded that DiNP and the other substances in the grouping do not meet the criteria under section 64 of CEPA. Notably, a 2025 peer-reviewed in-home study of Canadian children's bedrooms found DiNP above the toy-restriction threshold in several mattresses, which the study authors specifically flagged as a regulatory gap — the Phthalates Regulations cover toys and child-care articles but not mattresses. Regulatory — Justice Laws Canada · Government of Canada |
| Australia | NICNAS (now AICIS) assessed DiNP as a Priority Existing Chemical (PEC Assessment Report No. 35, published September 2012) for use in toys, child-care articles and cosmetics. It concluded that current risk estimates did not indicate a health concern from children's exposure to DiNP in toys and child-care articles even under the reasonable worst-case scenario at the time, and did not recommend new public-health risk-management measures. There are no restrictions on the manufacture, import or use of DiNP in Australia; this assessment has not been updated since IARC's 2026 classification. Regulatory — AICIS |
| Certifications | CertiPUR-US: certified flexible polyurethane foam must not contain phthalates regulated by the CPSC. The CPSC's permanent rule (16 CFR Part 1307) prohibits eight phthalates above 0.1% in children's toys and child-care articles — DEHP, DBP, BBP, DiNP, DIBP, DPENP, DHEXP and DCHP — so DiNP falls within the CertiPUR-US prohibition for certified foam. OEKO-TEX STANDARD 100 screens/restricts DiNP among the phthalates in certified textiles, with stricter limits for baby articles. GREENGUARD / GREENGUARD Gold is a low-VOC emissions certification; as a heavy, essentially non-volatile plasticizer, DiNP is not a target analyte of that emissions testing. None of these certifications specifically cover mattress cover fabric or PVC content the way they cover foam. Industry — CPSC · CertiPUR-US |
| The 72-hour test window | Largely missed. DiNP is a high-molecular-weight, essentially non-volatile SVOC plasticizer that migrates out of PVC and partitions into house dust and onto surfaces rather than off-gassing as a gas, so a short (~72-hour) VOC emissions chamber test does not reliably capture it; dust sampling or material-content (extraction) analysis is required instead, as the 2025 children's-bedroom study demonstrated by testing mattress material directly. Inferred — from the compound's volatility/emission profile versus the VOC focus of short chamber tests |
What it is
DiNP — diisononyl phthalate, CAS 28553-12-0 — is a mixture of branched-chain isomeric diesters used as a plasticizer to make rigid PVC soft and flexible. It became the dominant replacement for DEHP in flexible PVC after DEHP was restricted in children's products in the US (2008) and listed as a Substance of Very High Concern in the EU. Global demand data put DEHP at roughly 40% of the phthalate plasticizer market as of the mid-2020s, with DiNP as the clear second-largest and fastest-growing high-molecular-weight phthalate, driven specifically by manufacturers substituting away from DEHP. Industry — market data
DiNP is not chemically bonded into the PVC matrix — like DEHP, it's physically blended in, which is exactly why it migrates back out over time, onto surfaces, into dust, and into air, especially as the material warms.
How it relates to the bedroom / where you encounter it
DiNP is used broadly in flexible PVC products: vinyl flooring, wall coverings, automotive interiors, garden hoses, electrical cable insulation, and a meaningful share of vinyl mattress covers and crib mattress laminates — the same product category that made DEHP a fixture of the DEHP Atlas entry. Because DiNP is the compound manufacturers reach for specifically instead of DEHP, it shows up disproportionately in newer vinyl products, including many marketed for children.
The clearest bedroom-specific evidence comes from a 2025 in-home study that sampled bedroom air, sleeping-microenvironment air, and mattress material directly from 25 homes with children aged 6 months to 4 years in Toronto and Ottawa. Five of the mattresses tested contained DiNP above 0.1% by weight — the same concentration threshold that is legally prohibited in toys and child-care articles in the US, Canada, and EU. Mattresses are not covered by those restrictions. Peer-reviewed — Vaezafshar et al. 2025, Environ. Sci. Technol. Lett. The study's authors specifically called out this gap: a child's toy and a child's mattress can be made of nearly identical vinyl, but only one is regulated for phthalate content.
What the research says
The cancer classification is new and needs honest framing. In July 2026, IARC's Monographs Working Group classified DiNP as Group 2B — possibly carcinogenic to humans — based on sufficient evidence in animal studies, inadequate evidence in humans, and strong mechanistic evidence. Peer-reviewed — Sun et al. 2026, Lancet Oncology / IARC Monographs Vol. 142 The animal liver tumors that anchor that finding are widely believed to arise through activation of PPAR-alpha, a receptor pathway that drives cell proliferation strongly in rodent liver but appears to have much weaker relevance in primates — a mode-of-action distinction reviewed in a 2026 toxicology assessment that found no increase in hepatocyte DNA synthesis when cynomolgus monkeys were dosed with DEHP or DiNP under the same protocol that produces tumors in rodents. Peer-reviewed — Buerger et al. 2026, J. Applied Toxicology That mechanistic nuance is part of why IARC still rated the human evidence "inadequate" even while classifying the hazard as Group 2B — it's a real signal that current science can't yet translate into a confirmed human cancer risk.
Reproductive and developmental effects track DEHP's pattern, generally at lower potency. The CPSC's own 2014 Chronic Hazard Advisory Panel review — the science that produced the permanent children's-product ban — concluded that DiNP does induce antiandrogenic effects in animals, "although with lesser potency than other active phthalates," and recommended restricting it anyway because it contributes to the cumulative risk from other antiandrogenic phthalates a child is typically exposed to at once. Regulatory — CPSC CHAP 2014 A widely cited 2011 rat study found that perinatal DiNP exposure increased nipple retention, reduced anogenital distance, and altered sexually dimorphic behavior in male and female offspring — the same "phthalate syndrome" pattern documented for DEHP. Peer-reviewed — Boberg et al. 2011, Reproductive Toxicology, PMID 21075200 That paper has a 2016 corrigendum revising some statistical values, and an industry-authored 2017 critique disputing parts of the reanalysis, with a published rebuttal from the original authors — the direction of the reported effects was not overturned, but readers should know the paper has a documented, still-debated correction history.
Liver and kidney effects are dose-dependent and documented in animal studies. A 2020 study dosing mice with DiNP through the skin — a route directly relevant to a fabric sitting against skin all night — found oxidative stress and histopathological changes in liver and kidney tissue at higher doses. Peer-reviewed — Liang et al. 2020, Toxicology and Industrial Health These effects, and the liver tumors discussed above, generally emerge at doses well above typical background human exposure — the open question is how much dose margin actual bedroom-level exposure carries, which current biomonitoring in adults hasn't fully characterized for DiNP specifically.
What helps / what does NOT help
Helps: check what a vinyl mattress cover or crib mattress laminate is actually made of, especially for children. Because DiNP was picked specifically to replace DEHP, a "DEHP-free" or "phthalate-reduced" claim on an older product can be technically true while DiNP is still present in comparable amounts — the 2025 bedroom study found it in mattresses at concentrations exceeding the toy limit. Look for products that state PVC-free or phthalate-free outright, or that carry a certification (MADE SAFE, GOTS, OEKO-TEX STeP) that prohibits phthalates as a class rather than naming only DEHP.
Helps: replace soft, semi-translucent vinyl mattress covers with cotton, wool, or polyurethane-laminate alternatives. This is the same highest-impact intervention documented for DEHP, and it applies equally here since DiNP migrates out of PVC by the same physical mechanism — accelerated by body heat and skin contact over a full night's sleep.
Helps: regular HEPA vacuuming and damp-dusting. Because DiNP is a heavy SVOC that partitions into house dust rather than staying airborne, dust control is a meaningful exposure-reduction lever, mirroring what's documented for DEHP in indoor dust studies.
Does NOT help: relying on "BPA-free" or general "non-toxic" labeling. BPA and phthalates are different chemical classes entirely; a BPA-free product can still be full of DiNP. There is no enforceable definition behind "non-toxic" on a label.
Does NOT help: assuming a newer product is automatically safer than an older DEHP-containing one. The entire reason DiNP is common today is that it replaced DEHP — a genuinely newer vinyl product is more likely to contain DiNP specifically, not less likely to contain a phthalate at all.
Open research questions
- How EU, UK, and other regulators that concluded "no reclassification needed" for DiNP in 2018 will respond to IARC's July 2026 Group 2B finding — this Atlas entry will be updated as those reviews are announced. Speculation
- Whether the PPAR-alpha mode-of-action argument for reduced human relevance of the rodent liver tumors will hold up under IARC's own published Monograph 142 reasoning once the full text (not just the summary) is available. Speculation
- Direct biomonitoring linking DiNP body burden specifically to mattress and bedroom vinyl exposure, as distinct from the broader home (flooring, furniture, food contact) — the 2025 study measured mattress material and room air but not urinary metabolites in the same children. Speculation
- Whether US, EU, or Canadian regulators will extend the existing toy/child-care-article phthalate limits to children's mattresses specifically, as the 2025 study's authors recommended. Speculation
The Embr Exposure Ledger: Diisononyl phthalate
One chemical, several public questions, answered from independent datasets and joined here — the environment it shows up in, the body burden it carries, how it is regulated, and what actually reduces it.
Detection and body-burden figures are occurrence data, not a personal measurement or a health diagnosis. Part of the Embr Exposure Ledger — an open, cross-dataset chemical join (download the data), reusable with attribution.
Citations
- OEHHA. Diisononyl Phthalate (DINP) — Proposition 65 chemical listing. Listed as causing cancer, effective 20 December 2013 (State's Qualified Experts basis); NSRL 146 µg/day. oehha.ca.gov Regulatory
- US CPSC. 16 CFR Part 1307 — Prohibition of Children's Toys and Child Care Articles Containing Specified Phthalates. §1307.3(b). ecfr.gov Regulatory
- CPSC Chronic Hazard Advisory Panel (CHAP) on Phthalates. Final Report, July 2014. cpsc.gov Regulatory
- US EPA. Final TSCA risk evaluation for Diisononyl Phthalate (DINP), finalized 14 January 2025. epa.gov Regulatory
- ECHA / EU REACH. Annex XVII entry 52, Regulation (EC) No 1907/2006. reachonline.eu Regulatory
- Sun M, Glass DG, Josephy PD, Mancini FR, Ogawa K, et al. (2026). "Carcinogenicity of butyl benzyl phthalate, dibutyl phthalate, and diisononyl phthalate." The Lancet Oncology, published online 3 July 2026. DOI 10.1016/S1470-2045(26)00334-7 Peer-reviewed
- Boberg J, Christiansen S, Axelstad M, Kledal TS, Vinggaard AM, Dalgaard M, Nellemann C, Hass U (2011; corrigendum 2016). "Reproductive and behavioral effects of diisononyl phthalate (DINP) in perinatally exposed rats." Reproductive Toxicology, 31(2):200-209. PMID 21075200 Peer-reviewed
- Vaezafshar S, et al. (2025). "Young Children's Exposure to Chemicals of Concern in Their Sleeping Environment: An In-Home Study." Environmental Science & Technology Letters. PMID 40385563 Peer-reviewed
- Liang F, et al. (2020). "Oxidative damage in the liver and kidney induced by dermal exposure to diisononyl phthalate in Balb/c mice." Toxicology and Industrial Health, 36(1):30-40. DOI 10.1177/0748233719900861 Peer-reviewed
- Buerger AN, et al. (2026). "Mode-of-Action and Human Relevance Assessment for Diisononyl Phthalate-Induced Liver Tumors in Rodents." Journal of Applied Toxicology. DOI 10.1002/jat.70223 Peer-reviewed
Frequently asked questions
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Is DiNP the same as DEHP?
No — they're related but distinct phthalate plasticizers. DiNP (diisononyl phthalate, CAS 28553-12-0) is the compound that largely replaced DEHP (di-2-ethylhexyl phthalate) in flexible PVC after DEHP was restricted in children's products and listed as a Substance of Very High Concern in the EU. DiNP is generally judged less potent as an antiandrogen than DEHP in animal studies, but it is not inert — it carries its own regulatory restrictions and, as of July 2026, its own IARC cancer classification.
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Is DiNP banned?
In children's toys and child care articles, yes — the US CPSC permanently prohibits DiNP above 0.1% under 16 CFR 1307.3(b), and the EU restricts it above 0.1% in toys and childcare articles that can be placed in a child's mouth (REACH Annex XVII entry 52). In adult products — including most vinyl mattress covers, flooring, and furniture — DiNP remains legal and widely used with no concentration limit.
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Does DiNP cause cancer?
California's Prop 65 has listed DiNP as a carcinogen since December 2013, and in July 2026 the International Agency for Research on Cancer (IARC) classified DiNP as Group 2B — possibly carcinogenic to humans — based on sufficient evidence in animals and strong mechanistic evidence, though evidence in humans remains inadequate. The animal liver tumors are believed to occur through a PPAR-alpha activation pathway that is less active in primates than in rodents, which is part of why the human evidence stays inconclusive. It's a real hazard signal, not a settled human cancer risk.
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Should I worry about DiNP in my mattress cover?
It's worth checking, especially for a child's mattress. A 2025 study of 25 children's bedrooms found DiNP above the 0.1% toy-restriction threshold in 5 of the mattresses tested — a level that is completely unregulated for mattresses even though it's banned in toys. If your mattress cover is soft, semi-translucent vinyl (PVC), replacing it with a cotton, wool, or polyurethane-laminate cover is the single most effective step, mirroring the advice for DEHP.
Related compounds
Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress.
Last reviewed 2026-07-07. If you find a factual error, contact us.