Pfizer, Merck, GlaxoSmithKline and Johnson & Johnson are among the pharmaceutical companies with Boston-area operations, so they had employees stay home or stay in the office if they were already at work Friday.
Massachusetts Gov. Deval Patrick Friday morning requested that people stay put as law enforcement personnel search for suspects in Monday's Boston Marathon bombing.
"All Pfizer sites in the Cambridge/Boston area remain closed until further notice," Pfizer said in a statement. "Our colleagues have been instructed to follow the directions of law local enforcement."
Pfizer is based in Manhattan and has operations in Collegeville, Montgomery County.
Merck, which is based in Whitehouse Station, N.J., and has a big operation in West Point, Montgomery County, also told Boston-area employees to stay put.
"We are actively monitoring the events in the Boston area and following the official guidance provided by the Massachusetts authorities," Merck said in a statement. "The safety of Merck employees is our utmost priority. This morning all employees in the Boston area have been requested to stay at home and not travel to work. Those employees who have already arrived at our sites have been instructed to stay inside until further guidance is received."
London-based GlaxoSmithKline, which has Center City and Philadelphia suburban operations, also has people working around Boston, including researchers in Cambridge and Waltham.
"We have urged employees to follow local authorities’ direction about staying home," GSK said in a statement. "We’ve reminded employees of available company counseling resources if they are needed.
Johnson & Johnson, which is based in New Brunswick, N.J., and has multiple operations in the Philadelphia area, has a few employees at a research facility in Cambridge.
"The FBI and the Governor of Massachusetts have announced a shelter-in-place and travel restrictions to the city of Boston," J&J said in a statement. "We are complying with this request."