DHAKA, Bangladesh — As rescuers struggled on Thursday to reach survivors in one of the worst manufacturing disasters in history, pointed questions were being raised about why a Bangladesh factory building was not padlocked after terrified workers notified the police, government officials and a powerful garment industry group about cracks in the walls.

As the death toll neared 300, the owner of the collapsed building, the eight-story Rana Plaza, was in hiding, and the police and industry leaders were blaming him for offering false assurances to factory bosses that the structure was sound, leading to the decision to allow 3,000 workers return to work.

Pressure continued to build on Western companies that had promised after a deadly fire in November to take steps to ensure the safety of Bangladeshi factories that make the goods the companies sell. Activists combing through the rubble here have already discovered labels and documents linking the factories to major European and American brands, like the Children’s Place, Benetton, Cato Fashions, Mango and others.

PVH, the parent company of Calvin Klein and Tommy Hilfiger, and Tchibo, a German retailer, have endorsed a plan in which Western retailers would finance fire safety efforts and structural upgrades in Bangladeshi factories — although they first want other companies to sign on.