Charles Faddis' risk assessment of LNG transportation and storage ("Danger at our doorstep," March 31) misrepresents how truly difficult it is to exploit LNG as a weapon. As a point of fact a methane/air mixture is only explosive in concentrations from 5 percent to 15 percent; above 15 percent there is no explosion risk --meaning the densest parts of a release cloud are nonflammable. He also neglects to analyze the rate of vaporization during a release event and how this mitigates any real danger outside the area of release. His assertion about turning a highly insulated LNG tank into a thermal bomb is beyond ridiculous. More damage can be done with a hijacked gasoline tanker (which is not thermally insulated).
However, the public concerns about LNG are better applied to liquid hydrogen. If we ever adopt a "hydrogen economy," then every liquefied hydrogen storage tank, whether in a car or fixed, becomes a clear and present danger.
Hydrogen is explosive when mixed with air from 4 percent to 75 percent -- any small spill can easily explode.
Paul Spause, Hanover
The writer is an aerospace engineer.