SKOWHEGAN — The S.D. Warren Co. Somerset Mill will hold its first mill emergency response mock exercise, beginning at 7:30 a.m. Friday, June 2, simulating hazardous-material response.

About 150 people will take part in the exercises, with 75 from outside agencies. The drill will involve all of the mill’s emergency response teams, including the hazardous-materials team, fire brigade, security and medical department.