Investigations found that Li Lijuan, a former worker of Hangzhou Yusei Machinery Co Ltd, guilty of arson after she set fire to a warehouse on January 1, 2013, state-run Xinhua news agency reported.
Three young firefighters lost their lives attempting to extinguish the flames, Hangzhou Intermediate People's Court said in its verdict on the case.
Li, a native of Hangzhou City, started the fire using a lighter and boxes as revenge for a recent work adjustment, according to the court details.