Dalilan Kansa Da Kwal Tar ke Haifarwa

3,4-Benzopyrene dake cikin kwal kwal an gane shi azaman babban ciwon daji.

Wannan abu yana da yawa a wurare daban-daban, ciki har da hayakin masana'antu, taba sigari, shanyewar mota, kuma a cikin naman da aka shayar da su a lokacin barbecuing.