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Description of key information

28 Day and 90 Day Inhalation studies have been conducted on CAS 756-13-8.  The NOAEL in the 28 day study is 1000 ppm and the NOAEL for the 90 Day study is 300 ppm.

Key value for chemical safety assessment

Additional information

CAS 756-13-8 was administered to rats in a 28 day study and a 90 day study according to OECD Guidelines 412 and 413 respectively. In the 90 Day inhalation study and the 28 Day Inhalation Study, clinical chemistry changes were noted that would indicate liver effects. Absolute and relative liver weights were increased in both studies. Peroxisome proliferation was observed in all male groups and a weaker peroxisome proliferation was seen in high level females.   The peroxisome proliferation effects were greatly decreased by the end of the recovery periods. Some liver weight changes were still present at the end of the recovery periods. Increases in absolute and relative lung weights were also seen in the 28 day study but not the 90 day study. Histological changes were present in the liver and lung (28 day study only for the lung). In the 28 day study, accumulation of macrophages was seen in the mid and high dose male and female animals. These effects were not seen in the 90 day study. In the 28 day study, nucleolar enlargement was seen in in the livers of the males at each dose group. 

 

 

The 90 Day Inhalation NOAEL was determined to be 300 ppm. The NOAEL of the 28 Day Study was determined to be 1000 ppm. The NOAEL’s are based on the liver effects caused by peroxisome proliferation.

 

Peroxisome proliferation is a well documented effect in rats but one that has little relevance to human risk assessment. The study reports document this fact and the NOAEL of 300 is not considered relevant for human risk assessment. No other effects were noted at the 1000 and 3000 ppm doses in the 90 day study. Therefore, for purposes of human risk assessment, 3000 ppm is used as the dose descriptor.

Justification for classification or non-classification

The results of these tests do not meet the requirement to classify CAS 756-13-8 as dangerous.