[Data for substantiation of MPEL of 1,2,4-triazole in the workplace air]

1,2,4-Triazole belongs to the 3-d degree moderately dangerous compounds, according to the parameters of acute intragastric toxicity (LD50). Single and repeated applications of the substance on the skin of rats does not lead to local irritating or skin-resorptive effects. In the native state the substance produces moderate irritating effects on the eye mucosa of rabbits. It produces a moderately manifest cumulative effect of the functional character (Kcum greater than 5). 1,2,4-Triazole belongs to the 2-nd degree of danger according to LC50. The threshold of acute inhalational exposure (Li(mac)) 226.6 mg/m3, the threshold of chronic inhalational exposure (Lim(ch)), 19.8 mg/m3. The substance does not have mutagenic and embryotropic properties. 5 mg/m3 is recommended as the maximum allowable concentration for 1,2,4-triazole in the air of the working area.