At a glance
| Chemical family | Organophosphate flame retardant and plasticizer (isopropylated aryl phosphate ester, mixture of isomers) |
| CAS number | 68937-41-7 |
| Classification | Not IARC classified. Endocrine-disrupting activity demonstrated (estrogenic, anti-androgenic, adipogenic). Component of Firemaster 550. Rising in house dust |
| Where you encounter it | Polyurethane foam in furniture and mattresses (as Firemaster 550 component); electronics housings; house dust (rising concentrations) |
| Sleep micro-environment relevance | Found in house dust at increasing concentrations. Component of FR mixture used in PU foam mattresses and furniture. Exposure during sleep through dust ingestion, inhalation, and dermal contact |
Regulatory & certification status
| European Union | REACH registered. Not on the SVHC candidate list. Under assessment as part of the OPFR group for endocrine-disrupting properties. Regulatory |
| United States | EPA included IPTPP in the OPFR Action Plan (2015). Not specifically restricted. TSCA inventory listed. Regulatory |
| Canada | Under assessment as part of the Chemicals Management Plan organophosphate FR grouping. Regulatory |
| International | Not IARC classified. Not a Stockholm Convention POP. Under increasing scrutiny as a PBDE replacement with endocrine-disrupting and adipogenic activity. Regulatory |
What it is
IPTPP is a mixture of isomeric aryl phosphate esters — isopropylated derivatives of triphenyl phosphate (TPHP). Along with TPHP, EHDPP (2-ethylhexyl diphenyl phosphate), and brominated components, IPTPP is one of the four main ingredients of Firemaster 550 (FM550), the commercial FR mixture developed by Chemtura (now LANXESS) as a replacement for pentaBDE in flexible polyurethane foam. IARC has not evaluated IPTPP. Multiple studies have found that IPTPP activates peroxisome proliferator-activated receptor gamma (PPARgamma), promoting adipogenesis (fat cell differentiation) — raising questions about whether FR exposure contributes to obesity. IPTPP also shows estrogenic and anti-androgenic activity in vitro. Its concentrations in house dust have been rising globally as PBDE-treated furniture is retired and replaced.
Where it shows up in bedding
IPTPP enters the bedroom through polyurethane foam in mattresses and upholstered furniture treated with Firemaster 550 or similar OPFR mixtures. As foam ages and degrades, IPTPP migrates to the surface and enters house dust. IPTPP is semi-volatile and partitions between air and dust in indoor environments. Multiple dust surveys in North American homes have detected IPTPP, with concentrations generally increasing over the past decade. During sleep, exposure occurs through dust ingestion, dermal contact with contaminated surfaces, and inhalation of resuspended particles. The combination of IPTPP with TPHP and EHDPP in the same FM550-treated foam means these three compounds co-occur in dust.
Citations
- Stapleton, H.M. et al. (2012). Identification of Flame Retardants in Polyurethane Foam Collected from Baby Products. Environmental Science & Technology, 46(24): 13432-13439. Source Peer-reviewed
- Pillai, H.K. et al. (2014). Ligand Binding and Activation of PPARgamma by Firemaster 550. Environmental Health Perspectives, 122(11): 1225-1232. Source Peer-reviewed
- EPA (2015). Flame Retardants Used in Flexible Polyurethane Foam: An Alternatives Assessment Update. Source Regulatory
Frequently asked questions
What is Firemaster 550?
Firemaster 550 (FM550) is a commercial flame retardant mixture developed by Chemtura as a replacement for pentaBDE in flexible polyurethane foam. It contains four main components: TPHP, IPTPP (isopropylated triphenyl phosphate), EHDPP, and a brominated component (TBB or TBPH). FM550 has been widely used in furniture foam and mattresses since the mid-2000s PBDE phase-out.
Does IPTPP cause obesity?
IPTPP has been shown to activate PPARgamma — a receptor that promotes fat cell differentiation (adipogenesis) — in laboratory studies. This has raised the hypothesis that exposure to FM550 components through house dust could contribute to metabolic disruption. However, the causal link between IPTPP dust exposure and human obesity has not been established. The laboratory doses are higher than typical human exposures, and obesity has many contributing factors.
Related compounds
Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress.
Last reviewed 2026-07-08. If you find a factual error, contact us.