NTSB: Boeing 787 battery shows short-circuiting - Article Photos 4/5

National Transportation Safety Board's Joseph Kolly, holds an fire-damaged battery casing from the Japan Airlines Boeing 787 Dreamliner that caught fire at Logan International Airport in Boston, at the NTSB laboratory in Washington, Thursday, Jan. 24, 2013. The battery that caught fire in Boston shows evidence of short-circuiting and a chemical reaction known as "thermal runaway," in which an increase in temperature causes progressively hotter temperatures, federal accident investigators said. However, it's not clear to investigators which came first, the short-circuiting or the thermal runaway. (AP Photo/Manuel Balce Ceneta)