BOSTON -- A man driving a small plow died Monday when the machine crashed through a sidewalk grate.

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Man Described As Well-Liked

NewsCenter 5's David Muir reported that Ricardo Diaz, 39, was driving a Bobcat plow to clear a sidewalk in front of Massachusetts General Hospital at 11 p.m. when the plow fell 20 feet through a sidewalk grate.

When emergency workers pulled Diaz from the hole, he was still alive. He died later in the hospital's emergency room.

Hospital authorities said they don't know how the accident happened. Local and federal officials are investigating the accident.

Diaz's family gathered at the hospital Monday night.

"The family is doing all right under the circumstances," said Jeff Davis, of Massachusetts General Hospital. "They've come together. His wife and his brothers and sisters and 16 relatives were all here last night in the emergency department. Now they're home thinking about the arrangements they have to make."

Diaz had been working for the hospital since 1991. He lived in Chelsea but was originally from El Salvador.

Diaz was promoted four times at the hospital, and operating the plow was one of many mechanical jobs he had. Davis said he was well liked by the other hospital employees.