HUNDREDS of group rental tenants have been relocated from a downtown property that was turned from a former factory house into a group rental site.

Illegal structures have been demolished at more than 190 rooms in the Dongfang Building on Gaoyang Road in Hongkou District, and doors have been sealed with bricks to prevent the group renters from reappearing, according to the district government.

More than 400 tenants, all of them from out of town, once squeezed into rooms that were separated simply by wooden and plastic boards on the third and fourth floors.

The illegal rooms covered 3,000 square meters, including the rooftop of the building, posing severe fire and safety risks.

The 625-square-meter rooftop was developed into 46 rooms for renting, said Zhou Yang, deputy director with the neighborhood management department of Tilanqiao Subdistrict.

On the third floor, rooms were separated into split levels to maximize rental income. Electric wires twisted with each other, leading to major fire risks, Zhou said.

Demolishing has been completed on the illegally built structures on the rooftop, along with illegal structures on the third and fourth floors. Engineers are inspecting the building’s structure to ensure it is safe before further demolishing work is carried out.

“The subdistrict relocated all the tenants by the end of August. Many of them are happy to leave after being told about the safety concerns,” Zhou said.

“It is quite shocking to see group rental tenants living inside these illegal structures,” said Wu Weinong, an urban management officer with the district.

Wu said the wiring, air-conditioning and electric stoves in the rooms were a fire accident waiting to happen.

Workers demolished illegal structures in Dongfang Building, where rooms were separated by wooden and plastic boards.

The subdistrict and urban management authority had cracked down on group rentals in the building repeatedly, but every time after they had done so, the tenants sneaked back in, Zhou said.

The joint efforts this time aims to resolve the problem once and for all, he added.

The owner of the building, a local valve company, has been asked to turn the third and fourth floors of the building into offices, especially to serve startup companies in the district, Zhou said.

The building on 112 Gaoyang Road near the North Bund area, or the Huangpu riverfront in Hongkou, was built in the 1990s by the valve company as a factory house. The valve firm later rented the building to a compressor company.

Street stores operate on the first floor of the building, and there is a hotel on the second floor. These businesses are legal with licenses, according to the subdistrict.

However, the upper floors were separated into rooms and rented as residential apartments. They later became a major group rental site in downtown.

Though the rooms have been sealed this time, law enforcement officers will keep up patrols to ensure no tenants return, Zhou said.

Despite repeated efforts by the government to crack down on group renting, the practice remains rampant in Shanghai.

More than 500 cases of illegal construction and group renting — multiple tenants staying in one property — were recorded in Shanghai residents’ credit accounts in 2016, a new effort conducted by the city government to deter property owners abusing tenancies.

The offenses registered in the personal credit accounts will affect any applications for the city’s residence permit, as well as bank loans, job promotions and traveling abroad, according to Shanghai’s Housing and Urban-Rural Development Administration.

Multiple occupancy poses fire and gas leak hazards, as well as sanitation, security, and noise problems, officials said.

In May 2014, two firefighters were killed by a blast at a 13th-story apartment that had been rented to a group of tenants.

The blast occurred as they were tackling a blaze in the flat. An electrical appliance in the group rental apartment was later blamed for causing the initial fire.