PITTSBURGH — A worker wrongly put parts coated with flammable materials into an electric oven before it exploded at a Pennsylvania factory, killing a visiting employee, federal workplace safety officials said.

The federal Occupational Safety and Health Administration has proposed the Mersen USA plant in St. Marys pay a $7,000 fine.

Noah Nichelson, general manager of the plant, had previously blamed the explosion on “incorrect placement of materials in an otherwise safely operating curing oven.” Nichelson didn't immediately return calls for comment Thursday as to whether the company will contest the OSHA fine.

The Jan. 30 explosion killed 52-year-old Arwed Ralf Uecker, the global director of research and development for Mersen USA Bn Group, based in Boonton, N.J.

The blast also injured Neil Carter, 58, of Ridgway, a plant production supervisor. The status of his recovery was not immediately available Thursday.

Mersen manufactures parts for use in electrical power applications that can withstand high temperatures, and other graphite-based components.

WASHINGTON — More people applied for U.S. unemployment benefits last week, although jobless claims continue to be close to prerecession levels.Weekly applications for unemployment aid climbed 21,000 to a seasonally adjusted 311,000, the Labor Department said. The prior week's was revised up slightly to 290,000.The four-week average, a less volatile measure, rose 2,000 to 295,750. That continues to be close to averages that predate the beginning of the Great Recession in late 2007.When fewer employers shed workers, it suggests potentially rising incomes and increased hiring activity.Job openings have increased 17.6 percent during the past 12 months, while hiring has risen 9.3 percent during the same period.

ATLANTA — Coca-Cola is buying a 16.7 percent stake in Monster Beverage for $2.15 billion, with the world's biggest soda maker hoping to benefit from the surging popularity of energy drinks.The Atlanta-based company said Thursday it will also place two directors on Monster's board as part of the deal.Analysts had suggested for some time that Coca-Cola might acquire Monster at a time when its flagship soda business is flagging in developed markets. Monster, meanwhile, has cultivated a loyal fan base in part by focusing its marketing on skateboarding, snowboarding and other sports events.