2-(2-butoxyethoxy)ethanol

Endpoint summary

Description of key information

ORAL:

Mouse, male: LD50=2410mg/kg (fasted animals), 5530mg/kg (fed animals)

Rat, male: LD50=7291mg/kg (fasted animals), 9633mg/kg (fed animals)

Rat, male: LD50=6560mg/kg

Guinea pig, male/female: LD50=2000mg/kg

Rat: LD50=3305, 5560mg/kg

Rat: LD50>5080mg/kg

Rabbit: LD50=2200mg/kg

INHALATION:

LD50 greater than saturated vapour pressure

DERMAL

Rabbit, male: LD50=2764mg/kg

Rat: LD50>2000ml/kg (4 hour exposure only)

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

2 410 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

2 764 mg/kg bw

Additional information

A number of reliable key studies plus supporting information are available in multiple species for the acute oral toxicity of 2 -(2 -butoxyethoxy)ethanol. A well documented study which looked at both fasted and unfasted animals showed that mice were more sensitive than rats with fasted animals (not surprisingly) more sensitive than fed animals. The lowest value seen was 2410mg/kg as the LD50 for fasted mice. The full results are shown in the key information field. Four studies showed the rat LD50 to be in the range 3305 to 9623mg/kg. Single values for the guinea pig and rabbit were in the range 2000 -2200mg/kg.

There are two reliable studies plus supporting information which shows that acute toxicity by the dermal route is low. The available information covers toxicity in rabbits and rats. The key study showed a dermal LD50 of 2764mg/kg in the rabbit. The supporting studies showed dermal LD50's of 4000 -4120mg/kg and a limit study in the rat which shows an LD0>2000mg/kg .

In an acute inhalation risk assessment assay that followed the basic principles as described in OECD test guideline 403, both rats and mice were exposed to an atmosphere saturated with vapors of the substance 2 -(2 -butoxyethoxy)ethanol for a period of 2 hours. Documentation of clinical signs was performed over the 8-day study period. No mortality was seen with the rats but 3 out of 20 mice died within the observation period. There were no other adverse clinical signs in either species apart from evidence for some eye irritation were observed. This could have been due to aerosol exposure as the vapour generation method did not exclude this possibility. On the basis of this result, the substance does not warrant classification for an acute inhalation hazard.

Justification for classification or non-classification

The rat and mouse are the two species normally used for acute oral toxicity classification. The values obtained for these species are greater than the threshold for classification. Values for other species also fall outside the range for classification under either directive 67/548 or regulation 1272/2008

Acute toxicity data by the dermal route clearly shows that the LD50 is greater than the threshold for classification under either directive 67/548 or regulation 1272/2008.

The LC50 cannot be reached by inhalation exposure up to the saturated vapour concentration and therefore classification for this route is not warranted.