Residents have been staging protests demanding compensation for property damage from the government.
Thousands of people had to evacuate their homes after toxic chemicals were detected in the air following the blasts at the world's 10th-busiest port.
Some 17,000 homes were damaged by the explosions and their shockwaves.
The warehouse was storing hundreds of tonnes of sodium cyanide, far more than legally allowed, it has emerged.
It was was also within 500m (1,640ft) of homes, in violation of laws that require a 1km minimum distance.
On Tuesday, Xinhua quoted an unidentified executive from the company as saying: "The company has handled hazardous chemicals during a period without a licence."
The agency said documents showed the company was approved to handle hazardous chemicals between April and October last year.