Environmental tobacco smoke (ETS) is a complicated mix of substances and chemicals found in the indoor air as a direct result of tobacco smoking. Other than being a nuisance, long-term exposure to ETS is also linked to an increased risk of cancer, respiratory and cardiovascular disease. In the European Union (EU), over half a million deaths per year are estimated to relate to smoking, about 79,000 of which are thought to relate to ETS exposure alone. This e-fact is designed to assist and advise workers and workplaces in relation to the potential harm caused by ETS, make some comments relating to the EU legal situation and give information and advice about how to avoid ETS exposure. In reality, a combination of multiple approaches carried out by different mixes of people in worksites is likely to be required to effect sustained change for the better.