As the United States prepares to respond to the horrific terrorist attacks of September 11, the difficult task will be to choose between effective options while minimizing the costs. Environmental concerns might seem trivial and even unpatriotic at a time like this, but the environmental effects of military action pose long-term dangers that we would be foolish to ignore. Thinking in environmental terms right now shouldn't be surprising. We must be alert to the likelihood that aggression against the United States may increasingly take the form of environmental terrorism, including biological and chemical warfare. Conventional attacks also create environmental risks. Witness the concern about exposure to asbestos among World Trade Center rescue workers. Terrorists may not care about these things, but we should care. Our military response should be aimed at minimizing and mitigating, where possible, collateral environmental damage. Environmental losses are also casualties. They should be included in our strategic thinking about where and what to strike. This is in our national interest. Patriotism and environmentalism go hand in hand. As the President has made clear, our response will come at a price. One of the costs, which will affect all of us in the future, will be environmental degradation. Depending on where and how we strike, we risk exposing large populations, including our own troops, to lethal toxic substances. We have some experience with the long-term effects of exposure of military and civilian personnel to potentially hazardous chemicals such as the defoliant Agent Orange in Vietnam and a variety of toxic agents in the Gulf War. These health effects can be devastating. Just as terrorism knows no borders, neither do environmental problems. Those environmental damages that do not directly affect foreign civilians or our own troops will eventually come home to roost in the form of polluted air and water, destroyed habitats, and even climate change, which affects us all. Surely the environmental devastation caused by the Gulf War (remember the burning oil fields) should make us reflect. Environmental losses occurring on the other side of the world do not respect geographic boundaries. In addition to human casualties, our counterattacks could devastate fragile ecosystems. An ecosystem seems terribly abstract compared to the concrete image of those collapsing towers and the compelling figure of Osama bin Laden. But environmental problems are real and serious. Ecosystem health is critical to the survival of future generations.