Fire-blocking materials are being reinvented — because the old flame retardants were toxic

/ Technology / By

Most people think “fire safety” means alarms, sprinklers, and evacuation routes. But there’s a quieter layer underneath: the chemistry of the materials inside a building — whether a surface flashes, smoulders, drips, or forms a protective char.

A new wave of flame-retardant technologies is emerging because the old answer (many 20th‑century retardants) came with an ugly cost: toxicity. Regulators and buyers want safer materials and safer additives. That’s forcing a rethink of how we slow fires down, from wood treatment liquids to graphene-enhanced plastics and wildfire gels.

Why there’s a scramble for “new” flame retardants

Flame retardants aren’t a novelty — they’ve existed for centuries. What changed is trust.

The BBC notes that many 20th-century flame retardants are highly toxic, and a chemist interviewed in the piece describes a lack of investment in replacements until recently. When a whole category becomes politically and medically suspect, the market does what it often does:

  • it keeps using legacy solutions where it can
  • it removes them where regulation or liability forces its hand
  • then it rushes to find alternatives

That “rush” is where both innovation and hype live.

The boring truth: fire safety is about buying time

Almost every fire-retardant claim boils down to one outcome:

Can you slow ignition and spread long enough for people to get out and firefighters to work?

The BBC’s reporting frames it as “materials that can buy time,” which is exactly right. In many real incidents, minutes matter more than perfection.

Wood is back — so making wood safer matters more

Modern construction has revived timber in many settings (from interiors to engineered wood products). Wood has advantages:

  • renewability
  • structural performance in certain designs
  • predictable charring behaviour compared with some plastics

But wood still burns. So treatments that change wood’s burning behaviour become valuable.

Burnblock: a simple-sounding mechanism with big implications

The BBC describes a flame retardant product called Burnblock used on timber.

Key details reported:

  • a wood treatment company in Belfast uses a clear liquid containing Burnblock
  • the manufacturer won’t disclose the ingredients
  • Danish Technological Institute documentation suggests the active ingredient is a “natural component in the body,” plus citric acid and another “natural component in some berries”
  • the mechanism described is char formation + water release + oxygen reduction

Whether the “natural” phrasing is marketing or meaningful safety is a separate question. But the mechanism is plausible: if you can force a material to char in a stable way, you can create a barrier between flame and fuel.

The manufacturing reality: making wood fire-retardant is an industrial process

The BBC gives useful detail on how the treatment is applied:

  • vacuum to open wood pores
  • pressure to force fluid into the core
  • long controlled drying (days to weeks)

That matters because “flame retardant paint” is not the same as “material that is chemically altered through its volume.”

If a treatment penetrates the core, you can get more predictable performance and durability — but you also inherit operational constraints:

  • time
  • cost
  • process control
  • species-specific results

So adoption depends on whether builders will pay for the extra safety margin.

Where skepticism is healthy: the graveyard of ‘promising’ materials

A fire-retardants expert quoted by the BBC mentions that many ideas have fizzled out — such as clay nanocomposites that were a hot topic in the early 2000s.

This is the pattern to remember:

  • lab results are easier than commercial deployment
  • manufacturing consistency is hard
  • certification and standards take time

Fire safety is one of the least forgiving product markets: if your material fails, the consequences are catastrophic.

Plastics: the harder challenge

The BBC makes an important comparison:

  • timber tends to burn at a more fixed rate
  • plastics can burn at an accelerating rate

A chemist in the report calls polyethylene “solid gasoline.” That’s blunt, but it captures the problem: some plastics have chemistry that makes them eager fuel.

So “fire-safe plastics” is not just a building problem — it’s a materials science and regulation problem.

Graphene additives: promising, but watch the unknowns

The BBC describes an approach where graphene is added to plastics to slow fire spread.

Reported claims:

  • graphene forms a protective barrier to reduce volatile release
  • it can contribute to a char layer
  • it’s used in products like protective footwear and conveyor belts

The honest position from the report is also important: graphene’s mechanisms may not be fully understood.

In safety-critical settings, that raises two questions:

  1. Repeatability: does it behave the same across different plastics, additives, and manufacturing batches?
  2. Health after-fire: what happens to graphene particles in smoke and debris?

The company says there’s no data suggesting health hazards, and the industry continues to test. That’s not a red flag by itself — it’s just a reminder that “safer than toxic legacy chemicals” isn’t the same as “proven safe in all conditions.”

Wildfire gels: fire protection is moving outside the building

One of the most interesting parts of the BBC piece is wildfire-driven innovation:

  • gel-like retardants sprayed onto homes before wildfire arrival
  • materials that bubble into a protective aerogel under flame

This is a different use case from internal building fires.

Wildfire protection is about:

  • radiant heat
  • embers
  • exposure over hours
  • outdoor weathering

It’s a brutal test for materials. But it’s also a market that is growing because wildfire risk is rising.

The constraint that decides everything: standards and certification

Even the best chemistry won’t matter if it can’t clear:

  • building codes
  • fire test standards
  • insurance requirements

And those systems move slowly.

That’s why many “breakthrough” materials first appear in:

  • industrial belts
  • niche construction components
  • temporary structures

before they ever reach mainstream building materials.

What to watch next

  1. Independent test results and which standards are being met (and under what conditions).
  2. Ingredient disclosure pressure: “secret sauce” doesn’t age well in safety markets.
  3. Toxicity trade-offs: what replaces the legacy chemicals — and what new risks are introduced.
  4. Cost curves: can safer materials scale beyond premium projects?
  5. Wildfire-driven regulation: regions at high risk may start requiring new protective measures.

Bottom line

A safer building future probably won’t come from one miracle additive. It will come from a portfolio of improvements:

  • timber treatments that reliably promote protective char
  • plastics that burn less violently
  • new wildfire coatings that protect exteriors

The opportunity is real, because the old flame-retardant era left a toxicity hangover. But the bar is high: in fire safety, a “promising” material isn’t a product until it survives standards, manufacturing reality, and the messy physics of real fires.

Sources

n English