PORTSMOUTH, N.H. – Nearly 300 oil tankers, propane tankers and other commercial vessels travel into Portsmouth Harbor each year, all under the watchful eye of the seven-person Marine Safety Field Office.

Based at Fort Point on New Castle Island, the office keeps watch on the area from Portsmouth Harbor to Great Bay and all points between Kennebunkport, Maine, and the Massachusetts-New Hampshire border.

The staff is responsible for enforcing laws, regulations and international treaties relating to vessel inspections.

“We oversee commercial shipping, port security and we have a range of environmental protection roles,” said Lt. Kailie Benson, the office’s supervisor.

Commercial vessels larger than 300 gross tons coming from more than 96 hours away now are required to give 96 hours advance notice of their arrival, up from 24 hours before the Sept. 11 terrorist attacks. The vessels also are required to provide detailed crew lists and cargo specifications.

“All large vessels are subject to a rigorous review prior to even being allowed to enter the river,” Benson said.

Before ships get to the harbor, a security team from the office boards the vessel. After that initial look, the harbor pilot steers the boat into port for an extensive inspection.

For boats carrying liquefied petroleum gas, teams check emergency generators, firefighting systems, steering and general navigation safety, Benson said.

Along with the vessels, the Marine Safety Office also is responsible for the safety of the facilities along the Piscataqua River, including oil storage sites.

Under new laws, all such facilities must submit a security plan by November and must implement that plan by July 2004. Among the requirements is that employees are required to carry identification and all entrances must be policed.

“The new regulations are aimed at putting us in line with some new international guidelines,” Benson said. “Basically it increases the security requirements for vessels and facilities overseeing vessels.”

Jim Therriault, managing director of marketing and communications for Sprague Energy in Newington, said the company’s fuel terminals already meet many of the new requirements that will be enacted in the next year.

Sprague operates three terminals. To increase safety, Therriault said that a vessel never sits idle at the terminal – cargo is offloaded and the ship is sent back out to sea. Therriault also said that since Sept. 11 more security personnel have been hired to police the terminal.