Surrounded by countless broken windows, gutted offices and mountains of cigarette butts, Qin Tao is trying to rebuild his life and business a year after giant explosions rocked the Chinese city of Tianjin.

At least 165 people were killed in the blast, which devastated a swathe of the northern port, and 12 months on much of his office building -- around a kilometre away from the epicentre -- looks almost the same as it did a day afterwards.

"First the neighbourhood officials came and took notes and pictures, then the district government officials came and did the same, then the police and then city officials," said Qin, 36. "But still I haven't heard anything, nothing has been done."

In the late hours of last August 12, a fire broke out at a chemical warehouse owned by Rui Hai International Logistics.

When it exploded it sent a monumental fireball soaring towards the heavens, mangling structures kilometres away -- captured by social media users in what rapidly became the country's highest-profile industrial accident in years.

Fears of toxic pollution were rife, with cyanide levels in the disaster zone far above national limits, and it took several days before a visit by Premier Li Keqiang -- normally among the second wave of responders in China's official choreography for disasters.

In the aftermath, officials pledged to convert the blast site to a park and renovate the area, part of Tianjin's free trade zone that Chinese officials were promoting in Europe last month.

But a year later the blast site is still inaccessible, with a temporary blue metal wall ringing the perimeter.

Patrolling police prevented journalists getting a closer look, with a SWAT car parked on a highway overlooking the area to discourage anyone from stopping.

A brand new school next to the site sat empty and businesses were dark and locked, occasional groups of migrant workers the only signs of civilian life on the streets.

- Plunged into debt -

Before the explosions, Qin was preparing to open a logistics company, finally achieving the Chinese dream of becoming his own boss.

Unlike most businesses, he and his fellow tenants at the Fortune World Trade Center bought their offices, which are now rendered worthless.

They mounted a protest in May, hanging giant five-storey-high banners on a tower declaring: "Injustice! We are still waiting for a resolution, what a tragedy".

Police took them down within hours, but there was no official response.

"I've plunged into debt since the government won't help us," Qin told AFP. "I'm still paying off the loan from when I bought the office, but we never even started business, there's nothing I can do but hope to be saved."

Those whose homes were close to the blast site have fared marginally better. Authorities offered homeowners of one compound roughly 800 metres from the epicentre a government buy-back of their flats or funding for repairs.

But the sums on offer were not enough for either, according to Wei, a resident who would only give her surname.

"The price the government offered to buy the homes was too low, it wasn't enough to buy another apartment in the city," she told AFP. Many chose the repair option, she said, but the compensation only covered about 10 percent of her costs.

- 'Now we have nothing' -

Trucks still roll into the port area, but local businesses are suffering.

"Since the explosion business has dropped significantly," said Xuan, a manager at a firm in the same complex as Qin, who would only give his surname. "Chemical companies like ours have been affected especially hard, and volumes are down at the port."

Official statistics tell a different story. According to the Tianjin government, overall cargo volume at the port in the first half of 2016 was up 18 percent from the same period a year earlier -- before the explosion.

The blast remains a sensitive subject.

Afterwards, the official Xinhua news agency reported one of Rui Hai's owners was the son of the former port police chief, and the other a former executive at state-owned chemical company Sinochem.

Those connections helped the company get permits despite numerous safety violations, Xinhua reported.

Corruption is rife in China, and causes widespread anger with the ruling Communist party.

Former Rui Hai employees have complained to Chinese media that the company has become a dark mark on their CVs, with many out of work in what they say amounts to a blacklist.

The report -- like others published in the run-up to the anniversary -- was promptly deleted, and according to one journalist involved senior editors were admonished by authorities.

"All the companies here, we all tried to build something, but now we have nothing," Xuan said at the Fortune World complex. "We didn't cause this problem, but we are paying for it."