Environment

"

Environment and health

Most PIN flame retardants have an environmentally friendly profile, which means that they pose no harm to the environment and do not bio-accumulate .

In addition, they have a low (eco) toxicity profile and will eventually mineralise in nature. Due to these characteristics, none of the currently commercially used non-halogenated flame retardants are considered to be PBT (persistent, bioacculative,, toxic) or vPvB (very persistent, very bioacculative).

Manufacturers of flame retardants addressed data gaps and commissioned tests and studies , to provide information as required by the European chemicals legislation, REACH (1907/2006/EC). Under REACH not only hazard data, but also data concerning emissions, uses and end of life are gathered and made public. In the registration dossiers submitted to the European Chemicals Agency, detailed substance information including summaries of toxicity and eco-toxicity tests are available.

There are various independent, third party evaluations of non halogenated flame retardants as part of environmental programmes initiated by authorities, agencies or NGOs as well as life cycle studies. The majority of these evaluations specifically assess alternatives to brominated flame retardants, such as the ENFIRO project which was sponsored by the European Commission. These reports sometimes come to different conclusions on the same products, because of different criteria used and because not all authors had the same information available and in some cases, data generated by manufacturers has not been included.

Examples:

GreenScreen (Clean Production Action): a simplified methodology based on chemical hazards only (not exposure) used by several Ecolabels to verify environmental credentials of FRs, e.g. TCO, ZDHC. Here you find a (non-exhaustive) list of FRs which are Benchmark 2 and higher.
ChemForward started in 2018 and brings together hazard assessments from different sources in a harmonized way, assigning “hazard bands”.
Denmark EPA screening report on phosphorus flame retardants (LOUS October 2016). Concludes that 12 FRs do not pose high risk for any health, environment or accumulation end point (out of 28 P-FRs studied).
The EU-funded LIFE-FLAREX project identified non-toxic alternatives to some brominated FRs for textiles: ammonium polyphosphate (APP), poly[phosphonate- cocarbonate], magnesium hydroxide, aluminium hydroxide and aluminium diethylphosphinate (Alpi).
The EU-funded ENFIRO project (“Life cycle assessment of environment-compatible flame retardants”) investigated the substitution options for some brominated flame retardants and compared the hazard, exposure, fire and application performances risk and impact assessments of selected halogen-free flame retardants. The studies concluded (2013) that the following 12 PIN FRs are of low concern: Ammonium polyphosphate (APP), Aluminium diethylphosphinate (Alpi ), Aluminium hydroxide (ATH), Melamine polyphosphate (MPP), 9,10Dihydro-9-oxa-10-phosphaphenanthrene (DOPO), Zinc stannate (ZS), Zinc hydroxystannate (ZHS).

Environmental impact of fires

PIN FRs play an important role in preventing and limiting accidental fires. This brings significant environmental benefits.

Accidental fires cause injuries, deaths, trauma as well as businesses and property losses. They also have environmental impacts:

Pollution with smoke and soot,
Pollution by contaminated fire extinguishing waters
Impacts of fire response: water and foams used to fight the fire, equipment, fire service transport, resources used in fire clean up …
Resources consumed in replacement and disposal / demolition of damaged or destroyed buildings and contents (1). This is the biggest environmental impact of accidental fires.

Photo legend: “Fire Impact Tool – Measuring the impact of fire suppression operations on the environment”, F. Amon, J. Gehandler, R. McNamee, M. McNamee and A. Vilic, Fire Safety Journal, 120 (2020)

Smoke and gas caused by fires

Some PIN flame retardants and synergists can reduce smoke emission, both by preventing materials catching fire and slowing fire spread, and by specific mechanisms: char formation, which is a barrier to smoke emission, release of inert gases, catalytic reduction of smoke.

PIN flame retardants enable “LSZH” (or LS0H – low smoke zero halogen) materials, which are required in many applications where smoke emission can prevent escape (e.g. railways) and where smoke gas corrosivity must be prevented to protect electronic systems.

The total toxicity of gases emitted in fires is related to the quantities of materials burned and the fire conditions: more available oxygen will generally lead to cleaner combustion with water and carbon dioxide as main products and less harmful side products.

Acutely toxic components prevent escape, can cause injury and death:

narcotic: CO, HCN – deadly within minutes; but also CO2, O2-deficiency
irritants for eyes and breathing, impacting the lungs: HCl, SO2, NOx, aldehydes

Compounds with long term effects pose significant concerns for firefighters and other professionals repeatedly exposed to smoke or soot:

polycyclic aromatic hydrocarbons (PAHs)
halogenated dioxins + furans (PCDD/F)
mostly adsorbed to soot, so inhaled in smoke particles; may also be absorbed by skin contact

References:

Blais 2020 concluded that the UK Furniture Fire Safety Regulations were effective in that time before black smoke was five times longer in the UK room, total smoke produced was half, peak heat release rate was lower, and smoke toxicity was lower (PAHs, hydrogen cyanide and carbon monoxide).
Osimitz 2022 used ToxTracker and analysed individual VOCs and SVOCs (volatile and semi-volatile organic carbons). Conclusions are dependency on case-by-case fire conditions in individual rooms but with the FR-furniture room generally producing fewer and lower levels of SVOCs, in particular for carcinogenic SVOCs.
A study for the European Commission (2018) concluded that: toxic gases in fires are linked to furnishings and fittings, synthetic materials produce more smoke than natural materials. “Published data overwhelmingly show that flame retardants do not contribute significantly to either acute or chronic fire toxicity in real fires”
CREPIM tests of 94 different polymer / FR compound show that, despite wide variations in emissions for the same materials, addition of PIN FRs to polymers generally leads to similar or lower smoke emission and smoke toxicity compared to neat polymers, and that PIN FRs mostly show lower smoke density than halogenated FRs (source). This study did not include PIN smoke suppressant synergists, which could bring additional smoke and toxicity reductions…See also CREPIM literature study for pinfa.
LSZH ( Low Smoke Zero Halogen) cables reduce smoke emission and corrosivity “Evaluation of flammability and smoke corrosivity of data/power cables used in data centers”, D. Zeng et al., Fire Safety Journal 2020