(AP) - Demolition work has started at Greystone Park Psychiatric Hospital in Morris County.

A section of the roof was removed on Monday.

The hospital in Parsippany was state-of-the-art in the late 19th century. But it was ordered closed by then-Gov. Christie Whitman due to dwindling numbers of patients and incidents of on-campus assaults and escapes.

Members of the nonprofit group Preserve Greystone want to halt the work.

Preserve Greystone trustee Adam McGovern tells the Daily Record of Parsippany he sent an email to supporters to encourage them to attend Wednesday's Morris County freeholder board meeting. The group plans to present a petition supporting preservation.

The county will receive 165 acres of the site for open space use once demolition is complete.