i didn't know that. But i think its a bit impossible for me its a 1 gallon tank and its pretty thick can't squeeze it. I still have the seal on mine so i think its ok. It is a red cup thing that goes before the cap and there is a washer in there too. Seems pretty secure to me. i am not willing to dump 3/4 gallons of fuel and pay 22$ for a new gallon. Still yet to test though so once i rebuild a few things i'll be ready.