The US government will begin a superfund-style treatment program to clean up Agent Orange sites in Vietnam today, super-heating soil to 635 degrees Fahrenheit as it helps turn around decades of contamination. The high temperature treatment is part of a $43m joint project between the US and Vietnam, USA Today reports, cleaning a 47-acre site near Denang's commercial airport from dioxin, a chemical known to cause cancer, birth defects and other disabilities.
Ex-situ thermal treatment is one of several methods to address dioxin contamination, and has been widely deployed across the US in areas where toxic chemicals have been discovered in buried stores. The system sees the contaminated soil placed into sealed, special containers and heated to extremes, breaking down the Agent Orange into a combination of oxygen, carbon dioxide and other harmless substances.
The first site - currently closed to the public - will see workers dig down around 6.56-feet to excavate the affected soil. A second site is being evaluated nearby; in total, around 2.5m cubic feet are expected to be dug up and treated; it's possible the clean-up could use in-situ thermal treatment, which does not require the same degree of material movement, but does take longer.
Today's collaboration is the latest step in several years of work between the US and Vietnamese governments, which has seen the US spend around $60m in the country in the past five years. The active clean-up is the first such element of the project, however; previously, US experts helped lay a 6-inch concrete layer on top of the area, to prevent poor weather from creating mud that could carry the dioxin to other areas.
Even if the four-year project is a success, the clean-up will have addressed a comparatively tiny proportion of the overall Agent Orange deployment. In the nine years of dioxin's use, the US military sprayed the chemical across an estimated 5m acres, using around 20m gallons in the process.