US retail powerhouses including Walmart, Gap and Target have unveiled details of a “historic pact” to improve worker safety in Bangladesh, following the Rana Plaza factory collapse which left more than 1,100 people dead.

The retailers are among 17 US to form the Alliance for Bangladesh Worker Safety Initiative, which has attracted heavyweight political backing from former senator George Mitchell, famed as one of the key architects of the Good Friday Agreement in Northern Ireland.

It follows the Accord on Fire and Building Safety in Bangladesh, set up by European workers union IndustriALL, and signed by 70 retailers including H&M, Primark and Marks & Spencer.

Gap and Walmart had come under fire for refusing to sign that code because they were unhappy with certain aspects.

The Alliance for Bangladesh Worker Safety Inititiative said it has set “aggressive timelines and accountability for inspections, training and worker empowerment”.

The five-year plan calls for inspections of all alliance members’ factories within the first year; common safety standards to be developed within the next three months; inspections results that are transparently shared; and that all alliance factories actively support the democratic election and successful operation of worker participation committees in fac.tories

Members of the alliance will provide funding, which is currently $42m “and growing”, over the five-year period.  Some companies are offering an additional combined total of over $100m in loans and access to capital to “assist factory owners they work with in Bangladesh for factory safety improvements”.

In a joint statement, the chief executives of the alliance members said: “The safety record of Bangladeshi factories is unacceptable and requires our collective effort.  We can prevent future tragedies by consolidating and amplifying our individual efforts to bring about real and sustained progress.

“We believe the partnership and collaboration are critical to our success.  We are committed to working with other global brands in order to achieve swift change.  We’ll use the power of the newly created alliance to find other sources of funding to support additional infrastructure improvement, including working closely with government agencies around the world.”

Signatories of the separate European Accord this week agreed to initial inspections on clothing factories in Bangladesh to “identify grave hazards” and the need for urgent repairs within the next nine months. They have also guaranteed to repair unsafe factories and share data on their suppliers.