The Havre de Grace Activity Center is without heat or air conditioning after contractors hit the center's geothermal heating and cooling line causing a coolant leak Monday afternoon, fire officials said.

The contractors were laying fiber-optic cable for the Harford Metro Area Network, or HMAN, a countywide initiative to bring high speed broadband to the area.

First responders from the Susquehanna Hose Company, Maryland Department of Environment, Harford County Department of Parks and Recreation, Havre de Grace Police and Harford County Hazmat Team responded to the scene around 2:27 p.m., Chief Scott Hurst of the Susquehanna Hose Company said.

Hurst said first responders immediately started an investigation to determine the source of the leak, as well as to check for any potential toxic fumes in the building.

"We knew from the beginning it wasn't anything severe, but we had to figure out what it was," the chief said.

After about 20 minutes, Hurst said, investigators determined the leak was not a health or environmental threat. He said the leak was environmentally friendly anti-freeze and there was no danger to the activity center or to Havre de Grace Middle School, which is next door to the activity center.

Antifreeze leaked into a few nearby drains, but it will not be harmful to the community or the waterways, Hurst said.

The Havre de Grace Activity Center, located at 351 Lewis Lane, was closed Tuesday and will continue to be closed Wednesday, March 12 and Thursday, March 13, county government spokesman Ben Lloyd said Tuesday afternoon, citing the need to repair the heating system.

Lloyd said the repair crew had hoped to have the heating system fixed by Tuesday but encountered some complications.

"We hope to have it open by Friday," he said.

Monday's incident occurred just minutes before classes let out at Havre de Grace Middle School. Hurst said students were barred from exiting through the back door of the school for about 20 minutes, while officials investigated the incident and took readings inside the activity center to ensure there were no hazardous chemicals or gases.

The activity center was not evacuated during the investigation, Hurst said.

Monday's incident was the second involving installation of fiber optic cable in Harford County during the past six months.

In September 2013, a home in the 200 block of High Meadow Terrace in Abingdon caught on fire when a Verizon employee installing FiOS cable for Verizon drilled into the main electric line of the house. Fire investigators said the incident caused an estimated $70,000 in damage to the townhouse.