Newsflash: smoking is bad for your health. Okay so everyone knew that already, but until now the carcinogenic effect of cigarette smoke on lungs was not completely understood. Scientists knew the smoke caused cancer due to toxins, but how?

Now they've tracked it down to hydrogen peroxide contained in the cigarettes. By exposing human lung cells to cigarette smoke and hydrogen peroxide independently, they found the same cancerous development after a couple of days. Don't worry, this was done in a lab so nobody was sucking down peroxide for test results.

At any rate, the cells which were not exposed to anything were naturally clear of all signs. The connection has been made, so now companies can start making "safer" cigarettes without the chemical which they know causes cancer. Since they figured out exactly what triggers it, this could also lead to better treatment options!