From EIA website:

Proposed Natural Gas Liquids Realignment

EIA has reviewed the approaches and terminology that have been used by EIA and others to categorize and organize natural gas liquids (NGL) data. The review uncovered definitional inconsistencies in the use of terms such as NGL, natural gas plant liquids (NGPL), and liquefied petroleum gases (LPG) that are adversely affecting the quality and clarity of U.S. and international energy information on this important topic. Given this finding, EIA is now actively considering ways to realign and clarify terminology used in this area.

For more info or to register for the webinar:

http://www.eia.gov/petroleum/workshop/ngl/