Emergency operations officials in Harford County said persistent calls received about gas odors from numerous locations in the county early Friday morning appear to be related to fumes from an oil refinery in New Jersey.

No sources of gas were found in the county, but local fire companies were busy throughout Friday morning and into the early afternoon responding to calls of gas odors or suspected gas leaks.

Harford Emergency Operations spokesman Rick Ayers said early Friday morning the county was informed by state emergency operations officials that fumes from an industrial facility in New Jersey had been detected in the air in Harford and Cecil counties and in New Castle County, Del.

In a later statement, the county government said the fumes were from an oil refinery in Paulsboro, N.J., which is on the New Jersey shore of the Delaware River and across the river from Philadelphia International Airport.

"A large spill from an oil tank at the Paulsboro Refining Company facility in Gloucester County is not expected to impact the Delaware River or local water supplies," the New Jersey Department of Environmental Protection said in a news release. "Air monitoring also indicates there should be no health effects from odors caused by the spill."

Because of atmospheric conditions, the spilled product remained close to the surface in sufficient quantities to remain detectable by its odor, according to a news release from the Harford County Volunteer Fire and EMS Association.

The county sent out phone and text messages about the fumes from its emergency notification system starting around 8:30 a.m.

Calls to the county emergency operations center about gas odors appeared to be widespread, starting in the Havre de Grace area in the eastern end of the county around 7 a.m. and spreading to the Bel Air area shortly before 9 a.m., according to emergency radio transmissions.

In Havre de Grace, more than a dozen calls came from several locations in higher elevations, including Meadowvale Elementary School.

Fire and/or HAZMAT crews were dispatched to several of the calls, according to the radio transmissions.

A radio transmission monitored at 9:06 a.m. asked all HAZMAT personnel to contact the county dispatch.

Another call for a gas odor was received from the Darlington area at 9:12 a.m., according to dispatches.

At 9:14 a.m., radio transmissions announced a "Level 1" activation of emergency personnel throughout the county, basically putting them on alert.

At 9:20 a.m. another call for "odor of gas outside" went out for the Spenceola Farms neighborhood north of Bel Air.

As additional calls are received by the 911 center, they will be prioritized for dispatching purposes and will be handled by the fire service as "non-emergency" where warranted to reduce the risk to fire service personnel and other motorists, according to the association release.

By 11 a.m., the number of calls broadcast about the odor had subsided, with the latest call being at 10:49 in the 5100 block of W. Heaps Road near the Norrisville fire station.

Three other calls were received between 10 and 11 a.m. from Edgewood, Rocks and Havre de Grace.

No gas leaks were found, according to county government, which issued its statement at 11:02 a.m., saying that 35 calls had been received throughout the county and that emergency officials would continue to monitor the situation.

"The odor associated with this event poses no significant threat to public health and safety, and as winds are expected to shift, the odor should be leaving the area and dissipating during the day," the county's statement read.

By mid-afternoon Friday, the calls about gas odors had ceased completely.

Ed Hopkins, a member of the Bel Air Volunteer Fire Company, a Bel Air town commissioner, who carries the unofficial title of mayor, and head of external affairs for the Maryland Emergency Management Agency, or MEMA, said by phone around 11:15 that Bel Air fire company officials told him they had responded to four calls and did not find any gas leaks.

Hopkins said he had been testifying at a hearing in Annapolis most of the morning and was headed back to MEMA headquarters near Reisterstown to be briefed by the agency director.

Unless told otherwise by the county, Hopkins said, local fire companies like Bel Air would continue to respond to any calls about the odors.

"We have a policy to respond and investigate, regardless of the situation," he explained. "We aren't discouraging people to call. If they have a medical condition and are affected [by the fumes] or feel an emergency situation exists, they should call 9-1-1."