Scientific reports on second-hand smoke have stimulated legislation on clean indoor air in the USA, but less so in Europe. Recently, the largest European study, by the International Agency for Research on Cancer (IARC), demonstrated a 16% increase in the point estimate of risk in lung cancer for nonsmokers, a result consistent with earlier studies. However, the study was described by newspapers and the tobacco industry as demonstrating no increase in risk. To understand the tobacco industry's strategy on the IARC study we analysed industry documents released in US litigation and interviewed IARC investigators. The Philip Morris tobacco company feared that the study (and a possible IARC monograph on second-hand smoke) would lead to increased restrictions in Europe so they spearheaded an inter-industry, three-prong strategy to subvert IARC's work. The scientific strategy attempted to undercut IARC's research and to develop industry-directed research to counter the anticipated findings. The communications strategy planned to shape opinion by manipulating the media and the public. The government strategy sought to prevent increased smoking restrictions. The IARC study cost $2 million over ten years; Philip Morris planned to spend $2 million in one year alone and up to $4 million on research. The documents and interviews suggest that the tobacco industry continues to conduct a sophisticated campaign against conclusions that second-hand smoke causes lung cancer and other diseases, subverting normal scientific processes.