Beg pardon; I was mis-remembering and conflating several studies. My bad.
1) WHO funded, coordinated by its International Agency for Research on Cancer in Lyons, France.
P. Boffeta,
et al., 'Multicenter Case-Control Study of Exposure to Environmental tobacco Smoke and Lung Cancer in Europe',
Journal of the National Cancer Institute, 90 (7 October 1998) 19.
http://jnci.oxfordjournals.org/content/90/19/1440.full.pdf
650 lung cancer patients compared with1,650 healthy people. In all 7 nations and across all the range of subjects,they found no statistically significant additional risk from passive smoking at home or in the workplace. Withheld for six months before publication; when it leaked, WHO put out a lying statement headed 'Passive Smoking does cause lung cancer - don't let them fool you'.
2) 1960, the American Cancer Society commissioned a study of 118,094 adults including 35,000 smoker-non smoker couples, running 'til 1998.
It found 'no causal relation between environmental tobacco smoke and tobacco-related mortality. ACS tried to abort publication by withdrawing funding. No US journal would publish even after due diligence and peer review. Finally appeared in the May 2003 volume of the
British Medical Journal.
J. Enstrom and G. Kabat 'Environmental tobacco smoke and tobacco related mortality in a prospective study of Californians, 1960-1998',
BMJ, 17 May 2003.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC155687/pdf/el-ppr1057.pdf