It will cost more than $150m (£88m) and take at least 18 months for Bangladeshi garment factories used by American retailers to meet fire and safety standards.
The US Alliance for Bangladesh Worker Safety, whose members include Gap, Walmart and Target, released the findings in its annual report.
The cash is needed to allow factories to afford and access necessary safety improvements and for fire and safety training to be given to factory workers and management.
The alliance was formed in the aftermath of the Rana Plaza factory collapse in Savar, Bangladesh, which killed 1,129 garment workers and injured 2,515.
Since then it has inspected all 587 factories used by its 26 member companies, which also include Fruit of the Loom, Nordstrom and Macy’s. Ten factories were closed after failing to meet standards.
The report said progress to date has been encouraging but much work remains to be done. “There is no shortage of safety challenges confronting the garment sector in Bangladesh. But we are heartened by the progress that has been achieved in this first year in safety awareness, remediation, worker empowerment and ultimately in safety compliance,” it said.
Plans for the next year centre on “the hard work of sourcing the right equipment, installing necessary safety upgrades and complying with detailed corrective action plans, which will consume the energies of inspectors, brands, factory owners and engineers.”
Last week Bangladeshi authorities filed charges against 18 people over the collapse of the Rana Plaza factory, including the owner of the building.