Among the garment makers in the building were Phantom Apparels, Phantom Tac, Ether Tex, New Wave Style and New Wave Bottoms. Altogether, they produced several million shirts, pants and other garments a year.
The New Wave companies, according to their website, make clothing for several major North American and European retailers.
Britain's Primark acknowledged it was using a factory in Rana Plaza, but many other retailers distanced themselves from the disaster, saying they were not involved with the factories at the time of the collapse or had not recently ordered garments from them.
Wal-Mart said none of its clothing had been authorized to be made in the facility, but it is investigating whether there was any unauthorized production.