For decades, Tianjin has sought to emerge from the shadow of Beijing, its far more powerful and privileged neighbor, and to catch up with the rival port cities that pioneered China's economic transformation. The centerpiece of these ambitions has been the Binhai New Area, a vast stretch of industrial parks and skyscrapers along the muddy shores of the Bohai Sea about 30 miles from downtown.
Binhai boasts neither the skyline of Shanghai's Pudong district nor the export strength of Shenzhen in southern China. But more than half of Fortune Global 500 companies have invested in it. Airbus makes its A320 jet here. And President Xi Jinping has elevated its status with plans to make it part of a "supercity" that integrates Beijing with the region around it.
滨海新区既没有上海浦东的天际线，也没有位于华南地区的深圳的出口实力。它引以为傲的是，超过半数的财富500强(Fortune Global 500)企业在这里投资。空中客车(Airbus)在此地制造A320飞机。国家主席习近平计划整合北京与周围地区，使之成为一个"超级城市圈"，从而进一步提升了滨海新区的地位。
China's leaders began to experiment with the first special economic zones in the late 1970s to promote foreign investment and market-oriented policies. The districts promised tax breaks as well as freedom from over-regulation, and they grew so quickly that the rest of the country has since sought to emulate their approach. Binhai won special status in 1994.
Through the decades of rapid growth, however, the Communist Party has struggled to strike a balance between cutting red tape and enforcing rules to protect the environment, workers and public health. With little public scrutiny of their work, party officials are only occasionally punished for neglecting the latter, usually only after an accident. But they can count on being rewarded for pushing the limits for economic growth, with promotions — and opportunities for graft.
Even before the explosions, the Port of Tianjin, at the center of the Binhai district, had a reputation for lax oversight compared with its competitors. One state media report after the blasts likened it to "an independent kingdom." To Rui Hai's founders, Dong Shexuan and Yu Xuewei, it was the perfect place to set up shop in November 2012.
Mr. Yu, 41, had been deputy manager of the local branch of the state conglomerate Sinochem. Mr. Dong, 34, sold tires, cosmetics and wine, but his father was the police chief at the port, and that apparently helped them get the necessary fire safety, land and environmental permits.
"My connections are in police and fire," Mr. Dong told the official Xinhua news agency after he and his partner were detained. "When we needed a fire inspection, I went to meet with officials at the Tianjin port fire squad. I gave them the files, and soon they gave me the appraisal."
The news agency noted that Mr. Dong "did not specify whether there was a bribe or official misconduct."
But Rui Hai set up warehouses about half a mile from an apartment complex and a rail station, in violation of Chinese regulations requiring that hazardous chemicals be stored farther away from residential areas and transport hubs.
The environmental impact assessment ordered by regulators in Tianjin in 2013 made no mention of that fact. Instead, the Tianjin Academy of Environmental Sciences reported that 100 percent of the 128 residents it surveyed welcomed the facility in their neighborhood.
Former clients said they began using Rui Hai as early as February 2014. But it was not until May 4, 2014, that the Tianjin Transportation and Port Administration issued a temporary permit allowing the company to store and ship hazardous chemicals.
The license was effective retroactively, beginning April 16, and good for six months. At the bottom, it was marked, "This document is not to be made public." On Thursday, prosecutors said they were investigating the officials responsible for issuing the license, including the director of the transportation administration.
When that license expired, Rui Hai continued handling chemicals without one. "We didn't cease operations because we didn't think it was a problem," Mr. Yu told Xinhua. "Many other companies have continued working without a license."
Rui Hai may have been granted only a temporary license in 2014 because it had not yet obtained a safety certification, a process that the port administration outsources to private companies.
Ma Jun, a prominent Chinese environmental activist, said these safety consultants routinely skew their findings to satisfy corporate clients. "It's hard to stay in this business without compromises." he said.
The first company approached by Rui Hai declined to take the job, citing the facility's proximity to the residential complex, Mr. Dong said in the Xinhua interview. But Rui Hai shopped around, and found another firm, one that corporate records show is affiliated with the Ministry of Public Security. That relationship has led some Chinese journalists to describe it as a "red-hat intermediary," or a firm set up by officials to extract payments from businesses.
In a report issued in February 2015, the company overstated the distance between Rui Hai and the apartment buildings, the rail station and highways by hundreds of yards and asserted that it was in compliance with national standards.
It added that Rui Hai had "established a rather sound safety management system." Four months later, Rui Hai received a new permit to handle hazardous chemicals, good for three years.