4-tert-butyltoluene

Endpoint summary

Description of key information

ORAL 
Oral LD50 (male rat): ca. 1550 mg/kg bw (original value: LD50 = 1.8 ± 0.14 ml/kg bw) (Hine et al., 1954) 
DERMAL 
Dermal LD50 (rabbit): ca. 16880 mg/kg bw (95% C.I. ca. 11880 – 23940) (Hine et al., 1954) 
(Original value: Dermal LD50 = 19.6 ml/kg bw (95% C.I. 13.8 – 27.8)) 
INHALATION 
LC50 (female rat): ca. 1.5 mg/L (Original value: LC50 = 248 ± 36 ppm) (Hine et al., 1954) 
The substance, p-tertiary butyl toluene, causes damage to central nervous system after single application.

Additional information

ORAL

In an acute oral toxicity study (Hine et al., 1954), groups of 10 male, young adult Long-Evans rats were given a single oral dose of unchanged p-tertiary-butyltoluene (purity not given) at doses of ca. 690, 1030, 1380, 1720, 2070 mg/kg bw (original value: 0.8, 1.2, 1.6, 2.0, 2.4 ml/kg bw) and observed for 10 days.

Oral LD₅₀Males: ca. 1550 mg/kg bw (original value: LD₅₀= 1.8 ± 0.14 ml/kg bw)

p-tertiary-Butyltoluene is of MODERATE Toxicity based on the LD₅₀in males.

Besides unspecific clinical symptoms, signs indicating disturbance of the central nervous system were observed (stimulation, increase in activity, ataxia, confusion, tolerance of side-position, depression). Dyspnea was apparent early but was not severe until the terminal stages. General paresis, followed by recovery in four or five hours, was observed in several rats. Pathology revealed damage of the CNS, liver and gastrointestinal tract.

 

DERMAL

In an acute dermal toxicity study (Hine et al., 1954), 12 rabbits (no further data) were dermally exposed to p-tertiary-butyltoluene (purity not given; vehicle, if any, not given) at doses of up to 10.7 ml/kg bw (ca. 9210 mg/kg bw); totally eight rabbits were treated with 15.5 or 22.8 ml/kg bw (ca. 13350 or 19630 mg/kg bw, respectively). Animals then were observed for 10 or 14 days. No further details are given on the method.

Dermal LD₅₀: ca. 16880 mg/kg bw (95% C.I. ca. 11880 – 23940)

Original value: Dermal LD₅₀= 19.6 ml/kg bw (95% C.I. 13.8 – 27.8)

p-tertiary-Butyltoluene is of LOW Toxicity.

None of the 12 rabbits receiving up to 10.7 ml/kg bw showed evidence of intoxication, but at 15.5 and 22.8 ml/kg bw, five of totally eight animals showed evidence of severe alterations in physiology and subsequently died. The survivors showed only minimal toxicological responses. Abnormal signs included fibrillation, tremor, weakness, pupillary dilatation, nystagnius, reduction of body temperature, depression of cardiac and respiratory rates, excessive pulmonary discharge, opisthotonus, clonic and epileptoid convulsions, and depression of the central nervous system. Pathology revealed damage of the CNS and liver.

 

INHALATION

In an acute inhalation toxicity study (Hine et al. 1954), groups of 6 female, young adult Long-Evans rats were exposed by inhalation route to vapours of p-tertiary-butyltoluene (purity not given; vehicle, if any, not given) for 4 hours at concentrations of 0.817, 1.21, 1.81, or 2.72 mg/L (exposure method not further specified). Animals then were observed for 10 days.

LC₅₀Females: ca. 1.5 mg/L (Original value: LC₅₀= 248 ± 36 ppm)

p-tertiary-Butyltoluene is classified as being of HIGH Toxicity.

The principal toxicological responses were impairment of the central nervous and the respiratory systems. Pathology revealed damage of the CNS and liver.

 

Justification for classification or non-classification

Based on the oral LD50 in rats, p-tertiary-butyltoluene has to be classified as follows: Acute Oral Toxicity R 22 and Cat 4 (according to the Directive 67/548/EC and to the GHS criteria).

There is no need to classify p-tertiary-butyltoluene for acute dermal toxicity according to the Directive 67/548/EC and to the GHS criteria.

Based on the inhalative LC50 in rats, p-tertiary-butyltoluene has to be classified as follows: Acute Inhalation Toxicity R 23 and Cat 2 (according to the Directive 67/548/EC and to the GHS criteria).

Since a toxic effect on the central nervous system has been observed after administration via the oral and dermal route as well as inhalation, p-tertiary-butyltoluene has to be classified as: R 39/23/24/25 (toxic: danger of serious irreversible effects through inhalation, in contact with the skin, and if swallowed) according to the Directive 67/548/EC and GHS (UN) with STOT single Cat 1.