An ammonia leak at a frozen-seafood plant in Shanghai killed 15 workers on Saturday, Bloomberg reported, citing the local government. The city’s worst accident in almost three years also injured 25 workers of Shanghai Weng’s Cold Storage Industrial. They are in a stable condition, according to a statement on the city’s official Sina Weibo site. Investigators are examining buildings, equipment installation and daily monitoring and have hired professional organizations to audit the relevant equipment, it said. The accident comes three months after a blaze triggered by leaked ammonia in Jilin province killed 120 people.