Three people from a chemical plant are being investigated for an explosion that killed 15 workers and injured four in November 2011 in Xintai, Shandong province.

Another 13 people, including factory employees and Xintai city officials, received disciplinary and administrative penalties, according to a written reply from the provincial government to the incident investigation report.

The blast caused a direct economic loss of 18.9 million yuan ($3 million). It occurred at a melamine production facility of Shandong Liaherd Chemical Industry when workers were repairing a condenser on Nov 19.