A couple of quick scoops from Wiki - you might also like to try Googling 'Fallujah' while you're looking for ways to excuse US behaviour regarding civilian.
Jim Carroll.

White phosphorus (WP) is a material made from a common allotrope of the chemical element phosphorus that is used in smoke, tracer, illumination and incendiary[1] munitions. As an incendiary weapon, WP burns fiercely and can set cloth, fuel, ammunition and other combustibles on fire, and cause serious burns or death. It has been extensively used as a weapon since World War II. White phosphorus is used in bombs, artillery, mortars, and short-range missiles which burst into burning flakes of phosphorus upon impact. It is commonly referred to in military jargon as "WP," and the slang terms "Whiskey P.," "Willy," "Willie Pete, and "Peter" (derived from the phonetic alphabet in use during World War I) are still sometimes used by infantry and artillery servicemen.
In addition to its offensive capabilities, white phosphorus is also a highly efficient smoke producing agent, burning quickly and causing an instant bank of smoke. As a result, smoke-producing white phosphorus munitions are very common, particularly as smoke grenades for infantry, loaded in grenade dischargers on tanks and other armored vehicles, or as part of the ammunition allotment for artillery or mortars. These create smoke screens to mask movement, position or the origin of fire from the enemy.

Agent Orange is the code name for one of the herbicides and defoliants used by the U.S. military as part of its herbicidal warfare program, Operation Ranch Hand, during the Vietnam War from 1961 to 1971. Vietnam estimates 400,000 people being killed or maimed, and 500,000 children born with birth defects.[1]
A 50:50 mixture of 2,4,5-T and 2,4-D, it was manufactured for the U.S. Department of Defense primarily by Monsanto Corporation and Dow Chemical. The 2,4,5-T used to produce Agent Orange was later discovered to be contaminated with 2,3,7,8-tetrachlorodibenzodioxin, an extremely toxic dioxin compound. It was given its name from the color of the orange-striped 55 US gallon (200 L) barrels in which it was shipped, and was by far the most widely used of the so-called "Rainbow Herbicides".[2]During the Vietnam War, between 1962 and 1971, the United States military sprayed 20,000,000 US gallons (80,000,000 L) of chemical herbicides and defoliants in Vietnam, eastern Laos and parts of Cambodia, as part of Operation Ranch Hand.[3] The program's goal was to defoliate forested and rural land, depriving guerrillas of cover; another goal was to induce forced draft urbanization, destroying the ability of peasants to support themselves in the countryside, and forcing them to flee to the U.S. dominated cities, thus depriving the guerrillas of their rural support base and food supply.[4][5]
The US began to target food crops in October 1962, primarily using Agent Blue. In 1965, 42 percent of all herbicide spraying was dedicated to food crops.[5] Rural-to-urban migration rates dramatically increased in South Vietnam, as peasants escaped the destruction and famine in the countryside by fleeing to the U.S.-dominated cities. The urban population in South Vietnam more than tripled: from 2.8 million people in 1958, to 8 million by 1971. The rapid flow of people led to a fast-paced and uncontrolled urbanization; an estimated 1.5 million people were living in Saigon slums, while many South Vietnamese elites and U.S. personnel lived in luxury.[6]
Air Force records show that at least 6,542 spraying missions took place over the course of Operation Ranch Hand.[7] By 1971, 12 percent of the total area of South Vietnam had been sprayed with defoliating chemicals, which were often applied at rates that were 13 times as high as the legal USDA limit.[8] In South Vietnam alone, an estimated 10 million hectares of agricultural land were ultimately destroyed.[9] In some areas TCDD concentrations in soil and water were hundreds of times greater than the levels considered "safe" by the U.S. Environmental Protection Agency.[10][11] Overall, more than 20% of South Vietnam's forests were sprayed at least once over a nine year period.[5]