Answer:
The US military color coded it's ordnance during the Viet War; Red for chemical (tracer ammo), black for armor piercing, yellow for explosive, blue for target practice (inert). Agent Orange came in 55 gallon steel drums with an "orange" band painted around it. Chemical warfare in the US (at that time) were referred to as "agents."
Agent Orange was being phased out by 1970, and the US Army switched to ROME PLOWS to destroy jungles (forests). The US Army engineers drove those machines in circles (a whole line of them, each following the other) around a forest (jungle) until the jungle got smaller and smaller; by the time the former forest was only about a few acres in diameter, all of the animals would make a break for it, to include deer, to the surprise of many GI's who were conducting Rome Plow operations.
During the plowing, all of the forest animals had been moving closer and closer to the center of the former jungle, when there was little of it left, there would be dozens, possibly even hundreds of forest animals enclosed within those few acres. US mounted infantry and armored cavalry pulled security for the plows, by parking around the jungle's diameter. As the circle got smaller, the ACAV's of the Mech Infantry/Armored Cav would crank up their engines and relocate closer to the new smaller perimeter, in order to remain closer to the Rome Plows (to maintain security on them). When the forest animals made their break for freedom from the destroyed forest, the men opened fire on the animals, providing meat for the troops and ARVN units encamped nearby.