The LG Polymers plant had a history that predated its South Korean ownership. Originally an Indian operation, it was merged with McDowell Holdings, a subsidiary of the United Breweries Group, in 1978. LG Chem acquired it in 1997 and renamed it LG Polymers India. The facility stored 2,000 metric tons of styrene monomer in large tanks on the plant grounds. Styrene is a volatile organic compound used in manufacturing polystyrene and various plastics, and it requires careful temperature management: the monomer must be kept between approximately 20 and 25 degrees Celsius, because higher temperatures cause rapid vaporization. When India imposed a nationwide COVID-19 lockdown in March 2020, the plant shut down. The chemical tanks sat unattended for weeks, their refrigeration systems no longer monitored by the skeleton crew that remained.

Investigators believe a malfunction in the factory's refrigeration system allowed tank temperatures to climb past safe thresholds. Without functioning temperature sensors, which a later report would reveal the outdated tanks lacked entirely, the styrene began to vaporize undetected. The plant was in the process of reopening on May 7 when maintenance workers discovered the leak already underway. By then the damage was spreading. The vapor cloud drifted southeast across R. R. Venkatapuram, Padmapuram, BC Colony, Gopalapatnam, and Kamparapalem, covering a radius of roughly three kilometers. People who inhaled the gas experienced nausea, dizziness, and respiratory distress. Animals in the affected area were found dead or unconscious along roadsides. Late that night, police ordered the evacuation of everyone within a two-kilometer radius as a precaution.

The investigation that followed painted a picture of systemic negligence. LG Chem had acknowledged in a May 2019 affidavit that the plant lacked a legitimate environmental clearance from India's Ministry of Environment, Forest and Climate Change. The company argued that it had consulted the ministry and been told no clearance was required, but India's Environment Secretary contradicted this claim, stating that clearance was mandatory for any expansion or production change after 2006. The National Green Tribunal ordered LG Polymers to deposit an initial sum with the District Magistrate of Visakhapatnam and constituted a five-member fact-finding committee. That committee's report, issued on May 28, 2020, concluded that the storage tanks were outdated, lacked temperature sensors, and were managed by workers inexperienced in handling such dangerous chemicals. The verdict was blunt: the disaster resulted from "gross human failure" and a lack of basic safety norms.

Thirteen people died. Behind that number were families disrupted in the middle of the night, parents who could not protect their children from invisible gas, workers at the plant who had no warning of what was happening. The National Human Rights Commission declared the incident a gross violation of India's constitutional right to life. More than a thousand people required medical treatment, some on ventilator support. The Andhra Pradesh government directed LG Chem to remove 13,000 metric tons of material from the facility entirely, arranging two vessels to ship the chemicals back to the company's headquarters in Seoul. Experts who inspected the plant's other storage facilities after the leak warned that a second, larger catastrophe had been narrowly averted. The Vizag gas leak joined an unwelcome lineage of Indian industrial disasters, most prominently the 1984 Bhopal tragedy, that exposed the deadly consequences of insufficient regulation and corporate negligence.