Last weekend the concentrations of S02 reached 1150 micrograms/m3 in Zenica.
Coincidentally, the monitoring webpage was not working, so the city authorities could not declare the "alarm episode" since the precondition for this alarm is "three consecutive hours of concentration more than 500 micrograms/m3 of SO2 on all three monitoring stations." With five days delay, after the medial pressure of non-governmental organisations finally forced the responsible authorities to declare the alarm. Citizens were advised to avoid staying outside of their homes or to get away to the mountains near Zenica.
ArcelorMittal, the biggest polluter in the area, shirked partial responsibility by declaring that "they had no accidents, they perform as usual, and they decreased their emissions significantly during past years".