On 7 May 2020, the plant was re-opened following the lockdown implemented to reduce the impact of the COVID-19 pandemic.[9] The plant had 2,000 metric tons (2,000 long tons; 2,200 short tons) of styrene stored in tanks.[10] The tanks had been left unattended during lockdown.[11] Styrene monomer must be stored between 20–22 °C (68–72 °F) or else it will rapidly vaporize.[12] It is believed that a computer glitch in the factory's cooling system caused the temperature and vapor pressure to rise,[13] and between 2:30 a.m. and 3:00 a.m., when maintenance activity was in progress, the gas leaked from the plant and spread to nearby villages and areas.[14][15][10][8]