CHANGCHUN, Nov. 15 (Xinhuanet) -- No poisonous substance has been detected in the air after the blasts occurred in a chemical plant in Jilin City in northeast China's Jilin Province, local government said Tuesday.

    "After three-day monitoring, we can say the air quality in the city is OK," said an official with the city's bureau of environmental protection.

    The blasts took place at about 1:45 p.m. Sunday at a workshop in the No. 101 Chemical Plant of Jilin Petrochemical Company basedin Jilin City, some 100 km east to Changchun, the provincial capital.

    Some 30,000 residents and 12,000 university students had been evacuated shortly after the explosions for fear of further explosions and pollution by chemical maters.

    The environmental inspection station of the bureau carried out its emergency surveillance at about 2:20 p.m. Sunday. Three monitoring spots were established near the site of the accident.

    Benzene, aniline and nitrobenzene, all toxic substances were found in the air after the explosions on Sunday, but the density of the three kinds of toxic substances were under the standard level, said the official, who refused to give his name.

    As the air quality turns good, local residents and students returned on Monday. Enditem