That step, the detection and removal of unexploded ordnance in Danang, is part of a long and complex process to eliminate the painful legacy of dioxin, one of the chemicals used in Agent Orange and one of the world’s most toxic pollutants. The herbicide, which the U.S. military sprayed to defoliate areas where enemy troops had taken cover, has been blamed for health-related problems in millions of Vietnamese.

Although the U.S. and Vietnam have spent decades wrangling over who bears responsibility for cleaning up the damage, it wasn’t until 2001 that they agreed to begin working together to study the possible effects of dioxin contamination. Since then, the sides have had to determine the best method to clean it up.

In a statement, the U.S. Embassy in Hanoi on Friday called the removal of ordnance a “key first step.”

“The clearance of unexploded ordnance by the Ministry of National Defense is an excellent example of the strong collaborative relationship our two governments have built on the dioxin remediation project,” said Virginia Palmer, the U.S. charge d’affaires.

The project around the airport in Danang — one of three dixoin “hotspots” in Vietnam — will focus on an area of roughly 70 acres. After ordnance is removed, the soil will undergo a process known as “in situ thermal desorption,” in which the soil will be heated to extremely high temperatures to remove contaminants.

An official at the U.S. Agency for International Development familiar with the plans said that the process of construction and decontamination is scheduled to begin in early 2012.