The factory building had been expanded illegally, with additional floors stacked one on top of another. An engineer had declared it unsafe, and the thousands of people who worked inside, stitching garments for clothing brands from around the world, knew it was trouble. "That factory was very risky," said Khadiza Begum, who was working at Rana Plaza the day the complex collapsed, five years ago Tuesday. "It had weak pillars, it had narrow stairwells, it had no fire exits."

"We saw cracks in the building before it collapsed on us," she said.

The tragedy killed 1,134 people, many of them young women supporting extended families, and injured more than 2,500. It focused international attention on Bangladesh's role as the world's second-largest garment producer, and led the government and manufacturing associations to promise big improvements. Many of the world's top clothing brands said they would stop contracting with factories if they failed to improve safety for their workers. Five years later, the situation is complicated, according to a recent study conducted by the Center for Business and Human Rights at New York University's Stern School of Business.

"We have found tremendous improvement in the larger factories," that have signed onto two major safety programs organized by foreign brands, Paul Barrett, deputy director of the center, said in an email. "But two other categories -factories overseen by the government and subcontracting facilities not overseen by anyone -remain at risk."

The center's survey of conditions at Bangladesh's textile factories, found that workers at about 3,000 of the country's 7,000 factories are still exposed to life-threatening risks, ranging from a lack of fire safety equipment to serious structural flaws. The dangerous factories are often small, but sometimes subcontract work from larger factories that deal with foreign brands. Those factories rarely allow access for journalists, though the best-equipped factories are eager to show off their workplaces. S.M. Khaled is the managing director of the Snowtex Outerwear Ltd. Factory, a $42 million complex built after the 2013 disaster in the industrial suburb of Dhamrai, outside the capital Dhaka.

"The collapse of Rana Plaza was a wake-up call for us -for the industry and for the buyers," he said as he walked through the factory. "Look at my factory. Look around. I have done my best to keep it safe for the workers."

Textile exports are a huge business for Bangladesh, bringing in $28 billion annually, mostly from to Europe and the United States. Industry insiders guardedly admit that subcontracting remains an issue in the garment industry, with larger businesses sometimes contracting some work to smaller, less-safe factories. They insist those deals are being phased out.

Khaled said the established factories know they are being monitored by the international brands, and don't want to get in trouble by subcontracting. Worker safety should not depend on where the clothing is being worn, Roy Ramesh Chandra, president of Bangladesh's United Federation of Garment Workers, said in an interview.

"Authorities need to address all the factories -whether it is producing for export" or for Bangladeshis.