A blaze that killed at least 112 workers in Bangladesh Saturday occurred in a garment factory that was known to be unsafe by at least one of the U.S. companies that sourced goods from it.

The tragedy carries eerie echoes to both a Pakistani factory fire two months ago and the infamous Triangle Shirtwaist factory fire in New York in 1911. Exits were locked from the outside. Some of the victims died after jumping from the building to escape the fire. Many of those who were trapped inside the building were burned beyond recognition.

Sources say workers who tried to leave after hearing a fire alarm were told by their managers that the alarm had gone off in error, and that they should go back to work. Escape was also hampered by the fact that all of the staircases were internal and led down through the ground floor, which was where the fire originated.

"Had there been at least one emergency exit through outside the factory, the casualties would have been much lower," said Maj. Mohammad Mahbub, fire department operations director.

The factory was operated by Tazreen Fashions Ltd., a subsidiary of the Tuba Group, which supplies Walmart, IKEA and other major retailers in the U.S. and Europe. Polo shirts, fleece jackets and t-shirts were made at the factory, which employed approximately 1,700 people.

According to the Tuba Group website, Tarzeen received a “high risk” safety rating following an audit conducted for Wal-Mart in May of last year.

Wal-Mart spokesman Kevin Gardner said online documents indicating a "high risk" assessment after the May 2011 inspection and a "medium risk" report after an inspection in August 2011 appeared to pertain to the factory which burned. The August 2011 letter said Wal-Mart would conduct another inspection within one year.

Gardner was unable to say if that inspection had been conducted or if Wal-Mart was still selling products made in the factory.

Wal-Mart’s policy is to not place orders for one year with a factory that has received a high risk rating three times in two years. The May 2011 report was the first orange rating for the factory.

In its 2012 Global Responsibility report, Walmart identified fire safety as a “key focus” for Bangladesh sourcing, and noted that it had ceased working with 49 factories in the country in 2011 due to fire safety concerns.

Unsafe working conditions are common in Bangladesh, which has an estimated 4,000 garment factories.

A protest over the tragedy broke out today in the industrial zone where the deadly fire occurred, with thousands of people blocking the streets, some throwing stones at factories and damaging vehicles.

The government announced that tomorrow will be a day of national mourning, with the national flag flying at half-mast in honor of the dead.