Is it legal to sell faulty materials?

Is it legal to sell faulty materials?
It depends on what happens because the product is faulty.
If you are selling a computer that is faulty because the space bar sticks sometime, then that would be OK.

BUT, if you were selling a computer that will explode killing everyone in a 100 yard radius, then this is not OK.

Is the product dangerous? If not, then it should be OK to sell, as long as you tell the buyer what is wrong with it and don't try to defraud your buyer.