Defining LNG hazards
I just read your Aug. 20 editorial, “LNG tanker port would impact island lifestyle,” and thought I should mention some misunderstandings regarding LNG hazards.
I agree with your assessment that the Weaver’s Cove LNG terminal would severely disrupt activities on the water and impact property values. It would also present serious hazards; however, the comprehensiveness of the hazard mentioned in the editorial, I believe, is considerable but overstated.
While FERC considers the hazard zones (“zones of concern”) to extend just 2.2 miles from LNG ships, Dr. Jerry Havens, who developed the vapor dispersion hazard model, believes 3 miles is probably more accurate. Havens also has indicated that FERC and LNG developers improperly calculate LNG vapor impact zones. However, the 2.2- or 3-mile hazard zone does not mean everyone within that zone would be killed. There are three hazard zones: 1) 500 meters/one-third of a mile from the ship, 2) 1,600 meters/1- mile from the ship, and 3) 3,500 meters/2.2 miles from the ship. The hazard impacts would lessen with the increased distances of each zone.
Zone 1 presents the greatest hazards, where everyone would likely be killed by cryogenic temperatures, fire, explosion or asphyxiation.
Zone 2 presents a 30-second second-degree burn hazard to unprotected skin from a pool fire due to a conflagrated release at the ship. Confined vapor explosions, fire and asphyxiation could occur if combustion did not occur concurrently with the LNG release.
Zone 3 presents an explosion hazard from confined vapors, burn and fire hazard, and possibly an asphyxiation hazard.
In addition, actual impacts would probably not be symmetrical and would not entirely fill the areas of each of the hazard zones. The LNG vapors would likely be driven by wind, so the impacts would occur in relation to the wind direction and topography.
Another issue that may interest you is that the Weaver’s Cove Energy site violates world LNG industry terminal siting best practices. The Society of International Gas Tanker and Terminal Operators (SIGTTO; www.SIGTTO. org) represents over 95 percent of the world’s LNG industry. They research and promulgate best practices. Their publication “Site Selection and Design for LNG Ports and Jetties” (available only in hard copy for around £30 via Witherby’s Seamanship International) clearly states that, for the health of the LNG industry, LNG terminals should not be sited where vapors from a large LNG release would affect civilian populations. They also state that LNG terminals should not be sited up long and winding inland waterways where navigation hazards are greater. Also, in another publication of best practices, they indicate terminals should not be sited where there are conflicting uses of the waterway – now and into the future. Weaver’s Cove Energy clearly violates these best practices (see my LNG Terminal Siting Standards Organization website: www.LNGTSS.org).
Unfortunately, the U.S. Coast Guard and FERC ignore SIGTTO. They justify this by stating SIGTTO is merely advice and not law. Paradoxically, the U.S. Coast Guard spends considerable energy advocating adherence to best practices when it comes to other navigation issues.
LNG-related zone terminology is frequently misunderstood. Exclusion zones refer exclusively to LNG terminals, and are intended to prevent burn/fire injury to civilians and civilian assets. LNG ships have moving safety and security zones intended to prevent LNG ships from colliding with other vessels and to prevent attack from other marine sources. Also, while it would seem to make sense that the three LNG ship hazard zones should protect the public equally as terminal exclusion zones, they are based on different parameters. Exclusion zones are much smaller than hazard zones. Exclusion zones are designed (generally) to prevent civilians from the impacts of an LNG release, while hazard zones are not prohibited from engulfi ng large civilian populations who could be killed or injured.
I hope this information is useful.
Researcher and webmaster
Save Passamaquoddy Bay