4-nitrophenol

Endpoint summary

Description of key information

Data on the irritation potential of 4-nitrophenol has been reviewed in several reports; the information of which is provided under "discussion" below. 

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

Skin irritation:

In the Concise International Chemical Assessment Document (CICAD), data on dermal irritation of 2- and 4-nitrophenol are reviewed. Application of non-dissolved 4-nitrophenol resulted in slight irritation of the skin in one investigation performed according to US FDA guideline, whereas a study according to OECD 404 showed no skin irritating effects for non-dissolved 4-nitrophenol.

In the toxicological profile on nitrophenols, data on 4 -nitrophenol are reviewed and evaluated. Skin irritation studies in rabbits are cited using dry material and 4 -nitrophenol moistened with saline. Application of the dry material did not result in any skin reaction, whereas in the investigations using moistened material erythema and oedema were observed after treatment periods of 24 hours. Skin reactions were stated to be partially reversible by Day 21 after application.

In the NTP report, toxicity data of p-nitrophenol are summarized. A long-term toxicity study is cited where p-nitrophenol was applied via skin resulting in a dose-related pattern of skin irritation with erythema, scaling and crusting. However, the solvent used (ethanol) might in part have contributed to the development of the observed skin effects.

In the BUA report on 4 -nitrophenol, three studies regarding skin irritation are cited. In one of the studies, a 4 -hour exposure did not result in irritation of the skin, whereas a 24 -hour administration in another study showed slight skin irritation. After repeated administration to the skin in a reproductive toxicity study, dose-dependent irritative effects were observed accompanied by erythema, scale formation, scurf and cracking.

Eye and mucous membrane irritation:

In the Concise Chemical Assessment Document on Mononitrophenols, toxicity data on 4 -nitrophenol are reviewed and summarized. Three studies on eye irritation are cited in the report showing slight irritation in two of the studies after application of a 10% solution or non-dissolved material and strong irritation in a third study where non-dissolved material was used.

In the toxicological profile on nitrophenols, peer-reviewed toxicological data on 4 -nitrophenol are summarized. An eye irritation study is cited in which six rabbits were treated at 27 mg/kg of 4 -nitrophenoland observed for 21 days. Moderate to severe corneal cloudiness, blistered conjunctival tissue and corneal neovascularisation were observed. These effects were reversible in one of the six rabbits treated in the 21-day observation period. In a different investigation, corneal opacity was described in 4 of 6 rats exposed to a concentration of 4.003 mg/m3 of 4 -nitrophenol dust (sodium salt) for 4 hours.

In the BUA report, toxicity data on 4 -nitrophenol are reviewed. From the three studies performed, for two strong irritating effects of 4-nitrophenol on mucous membranes are cited, whereas a third study resulted in only slight irritation. 

In the handbook "Directory of microbicides for the protection of materials" the toxicological properties of 4 -nitrophenol are reviewed and it is cited that the substance is irritating to the eyes.

The overall evidence indicates that 4-nitrophenol causes irritation by all routes of exposure.

Effects on skin irritation/corrosion: irritating

Effects on eye irritation: irritating

Effects on respiratory irritation: irritating

Justification for classification or non-classification

Based on the results obtained in the investigations on skin, eye and mucous membrancne irritation and taking into account the provisions laid down in Council Directive 67/548/EEC and CLP (1272/2008/EC), PNF is classified as irritating by all routes of exposure.