UPDATED 7:40 a.m.: Mercury was detected in an operating room of Harford Memorial Hospital Tuesday, causing an isolation of all six rooms in the first floor department.

The rest of the hospital remains open, however all scheduled surgeries for Tuesday afternoon and Wednesday were cancelled. Emergency surgeries will be performed if needed.

According to Martha Mallonee, director of corporate communications for Upper Chesapeake Health, the incident involved one piece of equipment in a Tuesday morning surgery. That patient was recovering from surgery and in good condition at the hospital late Tuesday.

"The patient is fine, we are still assessing any exposure to mercury for him or her," Mallonee said late Tuesday.

The contaminated piece of equipment is a commonly-used instrument known as a bougie.

Mallonee said the patient and the patient's family were notified about the exposure, and the patient is being closely monitored. There were no other surgeries performed Tuesday in that specific operating room.

A dozen employees were checked for exposure to the mercury and sent home.

"Right now, we're on hyper-alert, because it is a hospital and our focus is patient safety," Mallonee said. "We want to be very careful that people understand that it's still safe to come to the hospital."

HAZMAT units were on site into Wednesday morning, lining to eastbound lane of Revolution Street along the north side of the hospital.

Mercury is a silver, metallic element which can be hazardous if ingested.

"We have been cleared by the Maryland Department of the Environment," Mallonee said. "They came early in the situation, assessed what our plan was, recognized that we had a good plan for the cleanup, distribution, all that, so they left."