Bio-antiflammables (flame retardants)

01Overview and value chain

Markers: [EC: EPA Safer Choice program / EU REACH halogenated-flame-retardant restriction & Horizon Europe biobased-materials funding (BIOSAFIRE) / EU mass-balance renewable-carbon certification | OECD: Bio-based materials | Regulator: EPA (USA), REACH (EU)]

Bio-antiflammables replace halogenated flame retardants — brominated and chlorinated compounds under increasing EU REACH restriction and US regulatory pressure over persistence, bioaccumulation and combustion-toxicity concerns — with phosphorus-based chemistry sourced from renewable carbon, lignin-derived biorefinery platforms, and bio-derived wood-fire-inhibitor formulations. Three distinct commercialization stages are visible in 2026: mass-balance renewable-carbon phosphinate flame retardants, where Clariant’s Exolit™ OP Terra retains the halogen-free DEPAL (aluminum diethylphosphinate) chemistry of its established Exolit™ OP line — UL 94 V-0 rating preserved even after several rounds of recycling — while sourcing 100% of its carbon content from renewable feedstock (renewable-based ethylene) under a supplier-certified mass-balance principle, the same certified-renewable-carbon model used elsewhere in bio-based chemicals; lignin biorefinery platforms feeding flame-retardant value chains, led by Vertoro (Geleen, Netherlands, founded 2017 out of the Brightlands Chemelot Campus/DSM/Maastricht University/TU Eindhoven public-private partnership), whose Goldilocks® platform converts agricultural and woody residues into scalable lignin blends at Technology Readiness Level 6, now supplying the biosourced flame-retardants value chain of the EU Horizon BIOSAFIRE project (22 partners across Europe, targeting ~80% biobased content across naval, railway, home-appliance and wood-coating applications); and bio-derived wood fire-inhibitor chemistry, where CitroTech Inc. (Oceanside, California, NYSE American: CITR) formed a 50/50 joint venture with Hexion Inc. in April 2026 to deploy CitroTech’s patented, EPA Safer-Choice-recognized fire-retardant formulation — the only long-term wood fire inhibitor in that program — across North America’s plywood, OSB and engineered-wood manufacturing base, replacing borate-based inhibitors that weaken wood under pressure treatment. Underneath these three commercializing platforms sits a substantially larger 2026 academic research base — phytic acid (extractable from beans, cereals and oilseeds at up to 28% phosphorus by weight), lignin-phytic-acid conjugates, tannin-modified-lignin phenolic foams, and boron-based natural-material fire retardancy — signaling that bio-antiflammables remain an earlier-stage, pipeline-heavy Industry relative to mature bio-based polymer and plasticizer categories, where commercialization has outpaced the research literature rather than trailing it.

The key directions of bio-antiflammables are:

1. Mass-balance renewable-carbon phosphinate flame retardants: Clariant’s Exolit™ OP Terra — chemically and compositionally equivalent to the established Exolit™ OP 1230 (DEPAL, aluminum diethylphosphinate), but produced with renewable-based ethylene sourced under a supplier-certified mass-balance principle, achieving 100% renewable carbon content by mass balance while retaining non-hygroscopic, water-insoluble properties, high phosphorus content (23.3-24.0% w/w), and UL 94 V-0 performance for polyamides (PA6, PA66) even after several recycling cycles.
2. Lignin biorefinery platforms for flame-retardant value chains: Vertoro’s Goldilocks® platform (TRL 6) transforms agricultural and woody biomass residues into scalable lignin fractions balanced for both upscaling practicality and molecular-range suitability, supplying the EU Horizon BIOSAFIRE consortium’s biosourced flame-retardant value chain (22 partners, ~80% biobased content target, five use cases across naval, railway, home-appliance and wood-coating sectors); founded 2017 by CEO Michael Boot and CTO Panos Kouris out of the Brightlands Chemelot Campus/DSM/Chemelot InSciTe/Maastricht University/TU Eindhoven partnership.
3. Bio-derived wood fire-inhibitor chemistry: CitroTech’s patented, science-backed fire-retardant chemistry — the only formulation recognized under the EPA’s Safer Choice program — penetrates wood fibers to prevent ignition without the pressure-treatment wood-weakening drawback of traditional borate-based inhibitors; validated through more than a year of testing with major North American wood-products companies; UL GREENGUARD Gold certified and ASTM E84 Extended compliant; the April 2026 50/50 joint venture with Hexion Inc. combines this chemistry with Hexion’s wood-adhesives manufacturing scale to reach plywood, OSB and engineered-wood producers.
4. Bio-based flame-retardant research pipeline (phytic acid, lignin-tannin, boron chemistry): a large, active 2026 academic literature base — phytic acid and its metal salts (iron, aluminum, sodium, lanthanum phytate) as phosphorus-rich bio-sourced flame retardants; lignin-phytic-acid conjugates and phosphorus/nitrogen-functionalized kraft lignin for particleboard and epoxy applications; tannin-modified-lignin phenolic foams for formaldehyde-free flame-retardant insulation; and boron-based fire retardancy for natural polymeric materials (wood, bamboo, nanocellulose aerogels) — represents the innovation pipeline feeding the next generation of commercial bio-antiflammable products beyond the three platforms above.

Sectoral value chain

[biomass residue / renewable ethylene / plant phosphorus feedstock] ──> [biorefinery fractionation / mass-balance feed substitution]
                                                                          │
                                                          (lignin fraction / renewable phosphinate / bio-inhibitor)
                                                                          │
                                                                          ▼
[finished flame retardant additive / wood treatment] <─── [compounding & formulation] <─── [certification testing (UL 94, ASTM E84, EPA Safer Choice)] <─── [chemical conversion (phosphinate synthesis / lignin functionalization)]

Value chain levels

Cross-cutting technologies of the sector:

• Mass-balance renewable phosphinate flame retardant (Mass-Balance Renewable Phosphinate Flame Retardant): Clariant’s Exolit™ OP Terra — DEPAL chemistry unchanged from the established Exolit™ OP line, but with renewable-based ethylene substituted at the synthesis feed under a supplier-certified mass-balance principle, achieving 100% renewable carbon content without altering performance, recyclability, or the halogen-free profile.
• Lignin biorefinery flame-retardant platform (Lignin Biorefinery Flame Retardant Platform): Vertoro’s Goldilocks® — a TRL-6 process converting agricultural and woody biomass residue into scalable lignin blends, now feeding the EU Horizon BIOSAFIRE consortium’s flame-retardant value chain across five industrial use cases at ~80% biobased content.
• Bio-derived wood fire-inhibitor chemistry (Bio-Derived Wood Fire Inhibitor Chemistry): CitroTech’s patented formulation — the only long-term fire inhibitor recognized under the EPA’s Safer Choice program — penetrates wood fibers without the pressure-treatment wood-weakening drawback of conventional borate-based inhibitors, validated over a year of testing with major North American wood-products manufacturers ahead of the April 2026 Hexion joint venture.
• Phytic-acid bio-based flame retardant (Phytic Acid Bio-Based Flame Retardant): phytic acid (myo-inositol hexakisphosphate, up to 28% phosphorus by weight, extractable from beans, cereals and oilseeds) and its metal-salt derivatives — the most actively researched bio-sourced phosphorus flame-retardant chemistry in the 2026 academic literature, applied to lignin conjugates, cellulose films, wool fabric and polylactic-acid nonwovens, though not yet represented by a commercialized branded product in this Industry’s confirmed 2026 sourcing.

02US

The US bio-antiflammables landscape in 2026 centres on wood-products fire protection, where CitroTech’s EPA Safer-Choice-recognized chemistry and its April 2026 joint venture with Hexion target the borate-based-inhibitor incumbents in plywood, OSB and engineered-wood manufacturing.

CitroTech’s EPA Safer Choice-recognized wood fire inhibitor, the Hexion joint venture

• CitroTech Inc. (Oceanside, California, NYSE American: CITR): a specialty chemical company delivering environmentally-safe fire-inhibitor solutions for the lumber and building-materials industry; its patented, science-backed fire-retardant chemistry is the only long-term fire-inhibitor formulation recognized under the EPA’s Safer Choice program, validated through more than a year of testing with several of North America’s largest wood-products companies; UL GREENGUARD Gold certified and ASTM E84 Extended compliant; engineered to penetrate wood fibers and prevent ignition without the pressure-treatment wood-weakening drawback of traditional borate-based inhibitors.
• CitroTech-Hexion joint venture (announced April 21, 2026): a 50/50 joint venture combining CitroTech’s fire-retardant chemistry with Hexion Inc.’s (Columbus, Ohio; American Securities portfolio company) wood-adhesives manufacturing scale and industry relationships, targeting plywood, oriented strand board (OSB) and engineered-wood manufacturers seeking built-in Class A fire resistance for commercial and residential construction; the venture is positioned to secure several of North America’s largest wood-products companies among its first commercial customers.
• EPA Safer Choice program: a voluntary EPA certification recognizing formulations that meet stringent human-health and environmental-safety criteria beyond baseline regulatory compliance — CitroTech’s is the only long-term wood fire inhibitor to carry the designation, positioning EPA Safer Choice (rather than a flame-retardant-specific mandate) as the operative US regulatory signal differentiating bio-derived fire-inhibitor chemistry from conventional borate and halogenated alternatives.

03CN

China is both a major manufacturing base for conventional (largely brominated and phosphorus-nitrogen halogen-free, not bio-based) flame retardants and, per 2026 domestic market-research publishers, a growing consumption market for flame-retardant chemicals broadly — but live sourcing in this cycle did not confirm a company-specific 2026 bio-based flame-retardant commercial launch on the scale of Clariant’s Exolit OP Terra, Vertoro’s BIOSAFIRE participation, or the CitroTech-Hexion joint venture, so no Chinese producer is tabled this cycle.

Market context without a confirmed bio-based producer event

• 产业调研网 / chinabgao.com sector reports: 2026-dated Chinese market-research reports project the flame-retardant chemicals market reaching roughly 2.8 million tons with price increases of 10-15%, driven by tightening “green barriers” reshaping the global supply chain — signalling regulatory and cost pressure on halogenated incumbents, but these are market-forecast publications rather than company-specific sourced events.
• Directional context: China hosts large-scale conventional flame-retardant manufacturing (including the world’s largest brominated flame-retardant producers), and Chinese producers are actively developing new halogen-free phosphorus-nitrogen chemistries (e.g. Shandong Unibrom Polymer’s 2026 precision-carbonization phosphorus-nitrogen system) — but these confirmed 2026 developments are halogen-free rather than specifically bio-based/renewable-carbon, so they sit outside this Industry’s bio-based scope rather than qualifying for the table; a bio-based-specific Chinese producer is a candidate for a future enrichment pass.

04EU

The EU leads bio-antiflammables commercialization on two fronts: Clariant (Switzerland) has shipped a mass-balance renewable-carbon phosphinate flame retardant at commercial scale, while Vertoro (Netherlands) supplies the lignin feedstock platform behind the EU Horizon BIOSAFIRE consortium’s flame-retardant value chain — with EU REACH’s restriction of halogenated flame retardants the primary regulatory driver of both.

Clariant’s mass-balance Exolit OP Terra, Vertoro’s Goldilocks lignin platform and BIOSAFIRE

• Clariant (Additives & Adsorbents business unit, Switzerland): Exolit™ OP Terra is chemically and compositionally equivalent to the established Exolit™ OP 1230 (DEPAL, aluminum diethylphosphinate) but sources renewable-based ethylene under a supplier-certified mass-balance principle for 100% renewable carbon content — non-hygroscopic, insoluble in water and organic solvents, 23.3-24.0% phosphorus by weight, and retains UL 94 V-0 rating for PA6/PA66 engineering plastics even after several recycling cycles; part of Clariant’s broader Exolit™ halogen-free portfolio (AP ammonium-polyphosphate line, EP epoxy-resin liquids, OP organophosphorus line) built on more than two decades of development and 500+ patents/patent applications.
• Vertoro (Geleen, Netherlands, founded 2017): a chemical startup spun out of the Brightlands Chemelot Campus/DSM/Chemelot InSciTe/Maastricht University/TU Eindhoven public-private partnership, founded by CEO Michael Boot and CTO Panos Kouris; its Goldilocks® platform (Technology Readiness Level 6) transforms agricultural and woody biomass residues into a versatile, scalable lignin-based feedstock intended to ultimately replace crude oil across materials, chemicals and fuels; within the EU Horizon BIOSAFIRE project, Vertoro has identified viable scalable lignin blends from its pilot plant for use as flame-retardant building blocks, balancing upscaling practicality against the molecular range needed for high-performance applications.
• BIOSAFIRE (EU Horizon project, coordinated from Zamudio, Basque Country, Spain; CORDIS project ID 101178218): a 22-partner consortium across Europe (including Italy, Turkey, Sweden, Poland, Switzerland) developing bio-based flame retardants from lignin and tannins following a Safe and Sustainable by Design approach, targeting ~80% biobased content while matching the fire-retardancy performance of conventional toxic benchmarks, demonstrated across five use cases in naval, railway, home-appliance and wood-coating sectors — the project is not a single company but the organizing EU vehicle connecting Vertoro’s feedstock platform to industrial flame-retardant applications.

05Leading companies and research institutes

06Tech stack and innovations

The bio-antiflammables stack spans three commercializing routes — mass-balance renewable-carbon phosphinate chemistry, lignin biorefinery platforms, and bio-derived wood fire-inhibitor formulations — sitting atop a substantially larger academic research base in phytic acid, lignin-tannin, and boron chemistry that has not yet produced its own branded commercial product in this Industry’s confirmed 2026 sourcing.

1. Mass-balance renewable phosphinate flame retardant:
   • Clariant’s Exolit™ OP Terra keeps the DEPAL (aluminum diethylphosphinate) molecule and performance profile of the established Exolit™ OP 1230 unchanged, substituting only the ethylene feedstock for a renewable-based, supplier-certified mass-balance equivalent — a “drop-in” renewable-carbon upgrade path that requires no reformulation or requalification by downstream engineering-plastics customers.
   • This mirrors the certified-renewable-carbon approach used elsewhere in bio-based chemicals (ISCC PLUS mass balance for resins and additives) — the flame-retardant sector’s version of decoupling renewable-carbon sourcing from product reformulation risk.
2. Lignin biorefinery flame-retardant platform:
   • Vertoro’s Goldilocks® process (TRL 6) fractionates agricultural and woody biomass residue into lignin blends calibrated for both industrial upscaling and the molecular range flame-retardant synthesis requires — a scalable feedstock platform rather than a finished flame-retardant product, positioning Vertoro as the upstream biorefinery layer that the BIOSAFIRE consortium’s downstream formulators build on.
   • The BIOSAFIRE project’s ~80% biobased-content target across naval, railway, home-appliance and wood-coating use cases represents one of the most systematic EU efforts to move lignin-and-tannin flame retardancy from academic demonstration to industrial-relevant scale.
3. Bio-derived wood fire-inhibitor chemistry:
   • CitroTech’s chemistry penetrates wood fibers directly rather than relying on pressure-treatment impregnation, addressing the mechanical wood-weakening drawback of conventional borate-based inhibitors while achieving EPA Safer Choice recognition — the only long-term fire inhibitor to do so — alongside UL GREENGUARD Gold and ASTM E84 Extended certifications.
   • The April 2026 Hexion joint venture is a go-to-market innovation as much as a chemical one: pairing a smaller specialty-chemical innovator’s formulation with an established wood-adhesives manufacturer’s production scale and customer relationships to reach plywood/OSB/engineered-wood producers faster than either party could alone.
4. Phytic-acid and lignin-tannin bio-based flame-retardant research pipeline:
   • Phytic acid (up to 28% phosphorus by weight, extractable from beans, cereals and oilseeds) and its iron/aluminum/sodium/lanthanum salts are the most actively published bio-sourced phosphorus flame-retardant chemistry in 2026, applied experimentally to lignin conjugates, cellulose/cellulose-hybrid films, wool fabric, and polylactic-acid nonwovens.
   • Parallel research tracks include phosphorus/nitrogen-functionalized kraft lignin for low-formaldehyde fire-resistant particleboard adhesives, tannin-modified-lignin phenolic foams for insulation, and boron-based fire retardancy for wood, bamboo and nanocellulose aerogels — a broad pipeline that, per this cycle’s live sourcing, has not yet crossed into a commercialized branded product distinct from the three platforms above.

07Value chains and production pipelines

Industrial pipeline of bio-antiflammables (EPA Safer Choice / EU REACH / mass-balance renewable-carbon certification)

┌───────────────────────────┐      ┌───────────────────────────┐
│ 1. Feedstock cultivation  │ ───> │ 2. Biorefinery            │
│    (biomass residue,      │      │    fractionation /        │
│    renewable ethylene)    │      │    mass-balance feed      │
└───────────────────────────┘      └───────────────────────────┘
                                                  │
                                                  ▼
┌───────────────────────────┐      ┌───────────────────────────┐
│ 4. Certification &        │ <─── │ 3. Chemical conversion    │
│    testing (UL 94,        │      │    (phosphinate synthesis │
│    ASTM E84, EPA Safer    │      │    / lignin functional-   │
│    Choice)                │      │    ization)                │
└───────────────────────────┘      └───────────────────────────┘
              │
              ▼
┌───────────────────────────┐      ┌───────────────────────────┐
│ 5. Compounding &          │ ───> │ 6. End-use & recycling    │
│    formulation            │      │                           │
└───────────────────────────┘      └───────────────────────────┘

Stage 1: Feedstock cultivation & extraction

Agricultural and woody biomass residue feeds Vertoro’s Goldilocks® platform in the Netherlands; renewable-based ethylene feeds Clariant’s Exolit™ OP Terra mass-balance chain in Switzerland; CitroTech’s bio-derived precursor sourcing is proprietary and not disclosed in confirmed 2026 sourcing; phytic-acid research feedstocks (beans, cereals, oilseeds) anchor the broader academic pipeline.

Stage 2: Biorefinery fractionation / mass-balance feed substitution

Vertoro’s TRL-6 process fractionates biomass residue into scalable lignin blends calibrated for downstream flame-retardant synthesis; Clariant substitutes renewable-based ethylene for fossil ethylene at the DEPAL synthesis feed under a supplier-certified mass-balance principle, with no change to the downstream DEPAL molecule.

Stage 3: Chemical conversion

DEPAL (aluminum diethylphosphinate) synthesis from renewable-based ethylene (Clariant Exolit OP Terra); lignin functionalization into flame-retardant building blocks within the BIOSAFIRE value chain (Vertoro); CitroTech’s patented, proprietary bio-derived fire-inhibitor chemistry engineered to penetrate wood fibers.

Stage 4: Certification & testing

UL 94 V-0 flammability rating verified for Exolit OP Terra even after several recycling cycles; BIOSAFIRE benchmarks Vertoro-fed formulations against conventional toxic flame retardants at ~80% biobased content across five use cases; CitroTech’s chemistry holds EPA Safer Choice recognition, UL GREENGUARD Gold certification, and ASTM E84 Extended compliance, validated through over a year of testing with major North American wood-products companies.

Stage 5: Compounding & formulation

Exolit OP Terra compounded into PA6/PA66 engineering plastics for consumer electronics, electrical installations and energy storage; BIOSAFIRE lignin-tannin formulations produced as flame-retardant powders for naval, railway, home-appliance and wood-coating applications; CitroTech’s chemistry formulated to penetrate wood fibers for plywood, OSB and engineered-wood treatment ahead of the Hexion joint-venture scale-up.

Stage 6: End-use & recycling

Consumer electronics, electrical installations (connectors, circuit breakers) and energy storage for phosphinate-based products (Clariant), which retain flame-retardant performance through several recycling cycles; commercial and residential construction lumber products (CitroTech/Hexion), replacing borate-treated wood that weakens under pressure treatment; naval, railway, home-appliance and wood-coating end uses under the BIOSAFIRE consortium (Vertoro feedstock).