Van Strum moved to Siuslaw National Forest in 1975. Shortly afterwards, helicopters sprayed the forests and water courses in the area with
phenoxy herbicides 2,4-D and 2,4,5-T, the 50-50 mixture used in Agent Orange (including surplus Agent Orange itself after it was banned by the military in Vietnam). Concerned by the apparent resultant negative effects on their family, animals and plants, Van Strum, her husband Steve and their neighbours co-founded Citizens Against Toxic Sprays (CATS). CATS gathered information from residents and undertook a community-wide public health survey. Although the ban was rescinded two years later, the work by Van Strum and others contributed to final cancellation of all 2,4,5-T registrations by EPA and a new national forest policy that favors selective harvests without herbicides. In 1987 Van Strum and Paul Merrell wrote
No Margin of Safety: a preliminary report on dioxin pollution and the need for emergency action in the pulp and paper industry. Originally published by
Greenpeace, it is now available within the pages of another volume. Over four decades of research and work by Van Strum on pesticide and poison cases, including lawsuits against the Forest Service, litigation by Agent Orange veterans, personal injury cases by exposed workers, and numerous other cases involving PCBs and dioxin, Van Strum amassed over 20,000 documents which she stored in a barn on her property. In 2017, she donated these to the Poison Papers digitalisation project. The papers include scientific reports, evidence submitted in courts of law, internal and external correspondence of chemical companies such as DOW and
Monsanto, and of government agencies such as the Environmental Protection Agency, often gathered via freedom of information requests. The documents are said to reveal corporate and government cover-ups of dioxin studies, collusion enabling continued registration of pesticides based on fraudulent or nonexistent studies, and decisions to continue marketing known carcinogens, mutagens and teratogens. The Poison Papers, also available with continuing additions through
Columbia University's Toxic Docs program are now available online for use by anyone seeking information on the dangers of using harmful chemicals in aerial herbicide spraying and attempts to end such spraying. Van Strum and
Tran To Nga, a Franco-Vietnamese environmental activist, The two have been involved in attempting to stop companies from producing, spraying, burning and dumping toxic defoliants such as those contained in Agent Orange and to force accountability for the harmful effects of these. In 2017 a ban against the spraying of pesticides on private timberland in
Lincoln County was approved by voters. The ban was overturned two years later by the state. The Lincoln County Community Rights group asked Van Strum to be the spokesperson for the
Siletz River ecosystem at the
Oregon Court of Appeal in a challenge to the rescinding of the ban. In June 2021, the Court of Appeal upheld the lower court's ruling without comment. == Private life ==