(2-hydroxyethyl)ammonium nitrate

Endpoint summary

Additional information

General

The known corrosive properties of the source chemical 2 -Aminoethanol are attributable to the high pH value of the free base in aqueous solution. This corrosive potential diminishes substantially when the free base is neutralised as observed in the reliable skin and eye irritation studies conducted with the Hydrochloride salt, i.e 2 -Aminoethanol hydrochloride (BASF AG, 1980; 78/908). Since the pH values of the Hydrochloride salt (2 -Aminoethanol hydrochloride) with pH 6 .8 to 7.4 and of the Nitrate salt ((2 -Hydroxyethyl)ammonium nitrate) with approx. pH 8 are comparable, the results of studies conducted with 2 -Aminoethanol hydrochloride are of high relevance for the irritation/corrosion hazard assessment. Based on similar acid/alkaline properties, comparable skin and eye irritating properties as the ones described for 2 -Aminoethanol hydrochloride (see below) can reasonably be attributed to the target chemical (2 -Hydroxyethyl)ammonium nitrate.

Skin irritation / corrosion

In a primary skin irritation study (BASF AG, 1980; 78/908), 6 Vienna White rabbits were dermally exposed to undiluted Härter 421 flüssig, i.e. 2 -Aminoethanol hydrochloride, for 5 minutes or 2 hours (short-term test, supporting information) and for 20 hours, using abraded skin (supporting information) or intact skin (key information, irritation scored at 24/48/72 hours). Animals then were observed for 8 days. In the main study, i.e. after 20 - hour exposure of intact skin, the mean erythema score (24/48/72 hours) for the 6 rabbits ranged from 1 to 2. Findings were fully reversible in 5/6 rabbits within 72 hours and in 1/6 rabbits within the observation period of 8 days. The mean edema score (24/48/72 hours) for the 6 rabbits was 1. Findings were fully reversible in within 72 hours. Testing on abraded skin (supporting data) with the same exposure duration resulted in higher scores of irritancy. On day 8, necroses indicative of strong irritancy were seen in 4/6 rabbits and scaling was observed in the 2 remaining rabbits. No or less severe findings were noted following short-tem exposure (supporting data): There were no findings in 2/2 rabbits (24/48 hours and 8 days) following exposure for 5 min, while exposure for 2 hours resulted in a mean erythema score of 0.5 and no edema in both rabbits. Under the conditions of this study, and with special regard to the long exposure duration of 20 hours in association with the use of occlusive dressings, the test substance showed skin irritanting properties but is not an irritant according to EU criteria.

A direct read-across assessment is not considered applicable for the endpoint skin irritation/corrosion. But reliable studies are also available for the source chemicals, 2 -Aminoethanol and Amonium nitrate. A supporting study in Vienna White rabbits conducted by means of the same method (similar to OECD 404) with 2 -Aminoethanol revealed corrosive properties (BASF AG, 1966; XV/305). These corrosive properties of 2 -Aminoethanol might trigger the irritant response observed for 2 -Aminoethanol hydrochloride. A reliable study conducted with the source chemical Ammonium nitrate (Hazleton Laboratories Europe Ltd, 1983; 0016) revealed no skin irritating/corrosive properties.

Eye irritation

In a primary eye irritation study (BASF AG, 1980; 78/908), 100 µL of undiluted Härter 421 flüssig, i.e. 2 -Aminoethanol hydrochloride, was instilled into the conjunctival sac of each one eye of 6 Vienna White rabbits. Irritation was scored by the method of Draize at 24, 48 and 72 hours. Slight conjunctival redness was the main test substance-related finding noted in 5/6 rabbits with mean scores (24/48/72 hours) ranging from 0.67 to 1.33. In 1/6 animals chemosis was observed after 24 hours resulting in a mean chemosis score of 0.67 for this rabbit. In 2/6 rabbits a very slight corneal opacity was noted at the 72 -hours reading only resulting in a mean score (24/48/72 hours) of 0.33 for each of the two rabbits. Reversibility was not assessed in this study (no 8 -day observation reported); however, there was a general trend towards reversibility within the 72 -hour observation period. Under the conditions of this study, the tested salt 2 -Aminoethanol hydrochloride was a slight eye irritant, but not subject to classification according to EU criteria.

Reliable in vivo data on the source chemical 2 -Aminoethanol (BASF AG, 1966; XV/305) revealed corrosive properties on the rabbit eye, mainly manifested as corrosion of the conjunctiva and nictitating membrane, and associated with purulent or bloody discharge and incrustration. No corrosive or severely eye irritating properties were observed in an in vitro bovine cornal opacity and permeability test conducted with the source chemical Sodium nitrate (NOTOX B.V., 2010; 493629). The subsequent in vivo eye irritation study conducted in 3 New Zealand White rabbits by the same laboratory (NOTOX B.V., 2010; 494137) revealed eye irritating properties of Sodium nitrate as evidenced by effects on the cornea, iris and conjunctivae. The corneal injury consisted of slightly dulling of the luster only. This was seen in 2/3 rabbits and was resolved within 24 hours after instillation in both animals. Irridial irritation (score 1) was observed in 2/3 rabbits and resolved within 24 hours in both animals. The irritation of the conjunctivae consisted of redness, chemosis and discharge and completely resolved within 7 days in all three animals. For conjunctival redness, the mean score (24/48/72 hours) was 2 in all three animals.

Respiratory irritation

No experimental data are available on respiratory irritation.

Justification for classification or non-classification

In view of similar acid/alkaline properties, (2 -Hydroxyethyl)ammonium nitrate is considered to possess slight to moderate skin and eye irritating properties comparable to those displayed by 2 -Aminoethanol hydrochloride. On this basis, the intensity of local effects potentially inducible by exposure to (2 -Hydroxyethyl)ammonium nitrate is considered to be below the relevant EU criteria for classification, i.e. (2 -Hydroxyethyl)ammonium nitrate is not considered to be subject to classification according to Directive 67/548/EEC (DSD) and Regulation (EC) No 1272/2008.

Considering acute toxicity data of the source chemicals idenitifed for read-across assessment (section 13), 2 -Aminoethanol is currently classified as C; R34 according to Directive 67/548/EEC (DSD) and as Skin Corr. 1B; H314 according to Regulation (EC) No 1272/2008 (CLP/GHS).