A US lawmaker is calling for more concrete commitment from US retailers to empower workers in Bangladesh's garment factories and make a lasting contribution to their safety.

As chairman of the Foreign Relations Committee, Senator Robert Menendez in June led a special hearing to discuss "Labour Issues in Bangladesh", following the Rana Plaza factory collapse in April, which killed more than 1,100 people.

Since then, 22 North American brands and retailers have set up the Alliance for Bangladesh Worker Safety - but Menendez says still not enough is being done to increase awareness and understanding of workers' rights in Bangladesh's garment factories.

In a letter to former US Rep Ellen O'Kane Tauscher, recently elected as chair of the board of directors of the Alliance for Bangladesh Worker Safety, he describes the Alliance as an "important first step" towards safer working conditions.

But he adds the action plan "does not adequately empower the workers in those factories to ensure their own safety."

He continues: "Our...hearing on labour issues in Bangladesh...consistently heard that if the workers of Rana Plaza had been in unions, their managers could not have forced them back into the building when collapse appeared imminent.

"Similarly, if the workers of Tazreen Fashions had been organised, managers could not have made them work through a fire alarm or kept exits padlocked.

"Bangladesh's factories will be truly safer when the workers can organize, speak and act together, without fear of retribution from factory owners or managers."

According to its plan, by this time next year the Alliance will have sent training teams into all of its 500-plus factories to educate both managers and workers on fire and building safety.

"I strongly urge you to expand this important programme to include education of workers on their rights and responsibilities with regard to organising and, more importantly, education of owners and managers with regard to accepting unions in their factories and cooperating with union leaders to improve working conditions."

Unlike the largely-European Accord on Fire and Building Safety in Bangladesh, which was initiated by IndustriAll and the Uni Global Union and includes trade union officials on its steering committee, the Alliance plan excludes trade unions.