At least 27 workers were taken ill after "increased emission" of carbon monoxide and methane from a blast furnace of Durgapur Steel Plant this morning, a day after a chlorine gas leak in Bombay Port Trust landed over hundred people in hospital.

Out of the affected workers, 24 were admitted in Durgapur Steel Plant (DSP) hospital where the condition of four was stated to be critical, chief of communications of DSP, B Kanungo said, adding they have been shifted to ICU.