Women who regularly used household or industrial cleaning products for 20 years had as much lung damage as if they’d smoked a pack a day over the same period, a new European study finds.

Scientists at Norway’s University of Bergen tracked 6,000 people’s use of cleaning products for over two decades.

Women who used who frequently used cleaning products had a significant difference in lung function from women who did not. The difference was less significant in men. It’s unclear why.