Safe Harbor?

Ships bringing liquefied natural gas from the Middle East pass regularly through Boston Harbor. Experts say there’s little chance of an LNG tanker going up in a fireball. Then why are city officials so worried? Should you be?

Every LNG tanker cruises past the piers and bridges of downtown and Charlestown before docking in Everett. Here are some of the security measures taken along the way:

Four days out
The LNG tanker is required to alert the Coast Guard of its approach and provide a manifest. The Coast Guard runs background checks on the crew. (Distrigas performs its own background checks before its ships sail.) The tanker must contact the Coast Guard again at 48, 24, 12, and 5 hours outside Boston Harbor.

Six to twelve miles out
Two Coast Guard officers board the tanker for safety checks and to watch for vessels that get within 500 yards. The Coast Guard also sends in teams of 12 to 24 officers for random security sweeps, though they’re more likely to spot check ships from Yemen.

Five miles out
A member of the Boston Harbor Pilot Association meets and boards the tanker. After safety and information protocols are performed, the pilot directs the ship toward the harbor at about 10 knots, or 12 miles per hour. 

Entering Boston Harbor
When the ship enters the North Channel, that’s the point of no return. Until then, the harbor pilot can decide to stop, no questions asked. From here, though, the pilot has committed. As the ship passes through the harbor, it hugs the East Boston shoreline, where the channel is deeper. The Coast Guard allows LNG tankers to enter only on clear days.

Pleasure Bay
As the ship slows, four tugboats lash themselves to its sides. (The tugs can haul the tanker and help it maneuver in case of emergency.) Here, the tanker enters the security zone, and law enforcement appears. No unauthorized vessels are allowed within 500 yards. At least five small boats — the Coast Guard, city and state police, and Massachusetts Environmental Police among them — escort the tanker. One or more choppers hovers above.

  • Robert

    Skikda, Algeria, had a catastrophic LNG accident in 2004, that killed 26 workers and injured 74.

  • Robert

    LNG storage tanks contain vapor (called “boil off”) at the top, above the liquid. It does not require pouring onto land or water to vaporize — it simply needs a slight rise in heat.

    The statement about a lit cigarette and LNG vapor flammability give a false impression of safety. Liquid gasoline will not burn until it vaporizes, either.

    LNG vapor is 3.7% more flammable than gasoline vapor. Methane (LNG) has a fuel-to-air flammability range of 5% to 15% (a 10% range), while gasoline has a flammability range of 1.4% to 7.6% (a 6.2% range). Neither will burn or explode outside those ranges.

    The Federal Government has defined LNG ship Hazard Zones that extend 2.2-miles from the ship. The hazards within those zones include cryogenic burns, asphyxiation, fire, thermal-radiation burns, and explosion.