Philip Britz-McKibbin (IMAGE) McMaster University Caption Philip Britz-McKibbin and his colleagues have discovered tobacco users in Canada are exposed to higher levels of cyanide than than smokers in lower-income nations. Credit McMaster University Usage Restrictions Editorial use only License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.