Nitrogen trifluoride

Endpoint summary

Description of key information

As NF3 is a gas, skin sensitisation is unlikely to be a relevant endpoint. Whilst no in vivo respiratory sensitisation data exist, NF3 reacts directly with Hb and therefore is unlikely to have any direct effects on acute pulmonary function / lung tissue. The effects seen following exposure to NF3 are attributed to the formation of MetHb, rather than lung targeted toxicity.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vitro

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

As nitrogen trifluoride is a gas, the dermal route of exposure is not relevant

Respiratory sensitisation

Link to relevant study records

Reference

Endpoint:

respiratory sensitisation

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

In the acute inhalation toxicity test, Deichmann and Gerarde stated that NF3 is a pulmonary irritant, however classical clinical signs of respiratory irritation, i.e. tachypnea and gasping are likely to be due to anoxia resulting from MetHb formation, rather than direct respiratory irritation. Repeat dose animal inhalation studies show that following inhalation of NF3 no specific damage to the olfactory epithelium in the nasal passages occurs, with also the respiratory epithelium remaining undamaged. These findings are unsurprising as NF3 is known to target red blood cells, oxidising Hb and preventing oxygen uptake, consequently decreasing oxygen content of the blood. The same is also characteristic of carbon monoxide (CO), which is not considered to be a respiratory sensitiser.

 

There are no reports of human intoxication from NF3, however human exposure is likely to resemble that of MetHb forming compounds and compounds which reduce the oxygen binding capacity of Hb (e.g. CO). Furthermore, NF3 does not contain any of the reactive groups: diisocyanates, acid anhydrides, cyanuric chloride or plicatric acid and therefore is deemed not to be a respiratory sensitiser.

Justification for classification or non-classification

As NF3 is a gas, skin sensitisation is unlikely to be a relevant endpoint. Whilst no in vivo respiratory sensitisation data exist, NF3 reacts directly with Hb and therefore is unlikely to have any direct effects on acute pulmonary function / lung tissue. The effects seen following exposure to NF3 are attributed to the formation of MetHb, rather than lung targeted toxicity. Therefore, NF3 has not been classified as a skin or respiratory sensitiser and no classification is therefore required.