Operation Downunder was a major internal effort by the Philip Morris (PM) tobacco company to define a comprehensive strategy to combat the effects of public information that environmental tobacco smoke (ETS, or secondhand smoke) is harmful to non-smokers.
Operation Downunder began with a meeting of mid-level PM executives held at a resort at Hilton Head, North Carolina June 24-26 in June, 1987. A 33-page internal PM document titled "Operation Downunder Conference Notes" recorded discussions held at the conference.  References in the document allude strongly to PM's awareness that ETS is not safe, that the mainstream scientific community wouldn't support them in their views that it is not harmful, and that they could not win this issue using logic. Some examples include the following quotes:
"ETS [issue is] not solvable with deductive reasoning...Come up with something company can get behind with $...We cannot say ETS is 'safe' and if we do, this is a "dangerous" statement...[We're] not going to get sympathy on our science by general scientific community...If smokers get message that their smoke kills others, is this not something major?"; and
"We've got to get to people on the street, but we are constrained because we can't say it's safe."
The document also contains a number of references concluding that the secondhand smoke issue will decrease PM's cigarette sales/profits:
"In U.S., ETS issue will have devastating effect on sales. E.G., parties, planes, etc."
"1. Problem -- [secondhand smoke issue] threatens number of smokers & number of cigarettes they smoke."
Another passage says:
- "Can you alter perception without touching on ETS? Yes. CHILL the rhetoric and bad science by SUING THEM."
Possible courses of action to take to address the ETS issue are listed in a 116-item, brainstormed "ideas list" in the document. Ideas on the list include:
- 33. Create science journal.
- 34. Create non-science journal.
- 49. Acquire major media vehicle.
- 50. Develop own radio programming.
- 62. Undermine [U.S. Surgeon General] Koop et al
- 66. Challenge tax exempt status of anti groups.
- 77. Help select next SG [Surgeon General].
- 81. Organize "spontaneous" protests on our issues.
- 92. Repeal smoking restrictions in target states.
- 105. Attack anti groups where they hurt.
- 108. Acquire an insurance company.
After all these ideas are listed, PM still admits: "We don't have anything to slam them with on health issue."
Operation Downunder ultimately gave rise to PM's "Accommodation Program," a strategy of broadening the secondhand smoke issue into one focusing attention on all virtually every other source of indoor air pollution, and promoting ventilation as the most reasonable answer to the problem of indoor tobacco smoke.
Operation Downunder also initiated efforts by PM to reverse public acceptance of secondhand smoke as a health risk. One PM Downunder strategy was to "use the legislative process to compel accommodation." Another was to "isolate anti-smoking forces." 
- "Project Down Under Conference Notes, Bates Number 2021502102, Philip Morris, June 24, 1987.
- Conclusions of Downunder", Bates No. 2024986950, Philip Morris, 1987 (approx)