A section of catwalk fell at least 40 feet to the floor inside a forestry mill near Bemidji, Minn., sending an employee crashing to his death, authorities and a corporate official said Monday.

Mitchell Harthan, 23, of Grand Rapids, Minn., fell to his death Saturday afternoon at the Potlatch Lumber Mill in Farden Township, according to the Hubbard County Sheriff’s Office.

The state ranks Potlatch as one of the safest companies operating in Minnesota, and this was the company’s first fatality at the facility since it opened in 1990.

Harthan was doing maintenance work about 40 to 50 feet overhead when “a section of catwalk he was standing on fell,” the Sheriff’s Office said.

Medical personnel declared Harthan, a Potlatch employee for the past two years, dead at the scene.

Minnesota OSHA said inspectors were sent to the mill to begin investigating why the catwalk fell, said agency spokesman James Honerman.

Mark Benson, a spokesman for the company based in Spokane, Wash., said, “We are deeply saddened. Our thoughts and prayers are with the employee’s family.”

Benson said there are “certain safety protocols” that Potlatch has in place for what Harthan was doing at the time, but the spokesman declined to say more while the investigation was underway.

From 2008-12, falls were the leading cause of workplace deaths reported to OSHA in Minnesota. There were 24 fatal falls over that period statewide among a total of 85 workplace deaths. Next was death by crushing, with 23, according to agency records.

In 2002, the timberland management giant was allowed to enroll in OSHA’s Minnesota STAR Program, which recognizes companies whose managers and employees “work together to develop safety and health management systems that go beyond basic compliance with all applicable OSHA standards” in an effort to prevent job-related injuries and illnesses.

Potlatch’s recertification in the program was extended for five years in 2010, Honerman said. There are currently 32 companies enrolled.

Potlatch has more than 1.4 million acres of timberland in Arkansas, Idaho and Minnesota. Its 205,000 acres in Minnesota are composed of mostly aspen and red pine.

Lynne Trembath, a friend of the family, said Harthan was a hard worker who was “very much adored at his job.” She said he never spoke to his family about any concerns for his safety at work.

Harthan wrestled at Grand Rapids High School and “loved to hunt and fish,” she said. After high school, he attended Mesabi Range Community and Technical College.