The installation of new liquefied natural gas (LNG) storage facilities in the United States to meet the demand of natural gas has brought increasing attention to LNG safety issues. Because of its highly flammable nature, one of the major hazards LNG poses is the formation of a flammable vapor cloud from any accidental release, which may result in a massive fire. The safety measures to prevent and mitigate an accidental LNG release are critical to protect employees and the public from injury or harm. The water spray curtain is currently a recognized technique to control and mitigate may toxic and flammable vapors. Much theoretical and experimental work has been carried out to determine the effectiveness of the water spray curtain in dispersing heavier vapor. However, LNG vapor dispersion behaves differently other dense gases due to its low molecular weight and extremely low temperature. Previous studies show that water spray curtains can enhance LNG vapor dispersion from small spills. However, to develop comprehensive and structured engineering guidelines for the design of an effective water spray curtain for controlling LNG vapor many key questions still remain unanswered. In this context, it is essential to carry out research to understand the effects of water curtain on LNG vapor clouds. An experimental methodology to study the LNG vapor dispersion behaviors with the application of water spray curtain is presented in this article. This field experiment involved the fundamental study of forced dispersion dilution due to air entrainment and heat exchange to determine the effectiveness of water spray in reducing the LNG vapor "exclusion zone." This article discusses and outlines the experimental method and some results based on gas concentration data analysis to emphasize the observed effectiveness of water spray curtain on LNG vapor dispersion. (C) 2008 American Institute of Chemical Engineers Process Saf Prog Prog 27: 345-353, 2008