Many people are unaware that even smoking away from babies or pregnant women presents a risk, according to US research.
Poisons in cigarette smoke can linger on fabrics or hair, but a survey of 1,500 households found that fewer than half of smokers knew this.
Only a quarter had strict rules about not smoking in the house, according to the report in the journal Pediatrics.
BBC NEWS | Health | Warning over 'third hand smoke'
Guess I'll have to stop smoking all together. I'd thought restricting smoking inside my office at home was enough for my girls...