The USA will never admit to any responsibility
for the after effects of spraying Agent Orange,
or Agent White, or Agent Blue
(and I believe there were two or three other
Agent “colors” that had various effects on vegetation),
as doing so would expose the USA to world condemnation
for using chemicals in war against an enemy,
knowing full well what the results would be.

Chemical warfare is outlawed by the Geneva Convention,
to which the USA is a signatroy sponsor,
and the lawsuits would be financially crippling to the USA,
and in short order the USA would become the equivalent
of a third-world country, with no recourse, and no way to
recoup the losses (financial as well as political) which would
result from those lawsuits.

So the United States will absolutely not admit to such demands
as admitting to a damn thing regarding the use of Agent Orange
or other defoliation agents.

Just like the US government will never tell us what is known
about the assassination of John Kennedy, or his brother,
it is just something that they hope will eventually pass away
into the darkness and graying dimness of ancient history.

It may, and it may not.

I do remember, early in my military career, while in NY City,
seeing a film that was released by two of the companies
concerned with chemical agents that were being considered
for use in Vietnam, and the companies told the US government,
on camera, what the effects of use of those chemicals
could likely be, and the film was accurate and deadly.

The government got hold of those films (including copies),
and disappeared them, and then denied ever having seen such
films or having anything to do with it at all.

REMEMBER: You can trust your government completely. —
…just ask any Native American Indian.

‘nuff said?