Weak 2 x 12 Stair Tread

This is real common when installing the treads most carpenters don't examine the lumber. These weak spots should be avoided by cutting them out before they are installed. As you can see in the picture above this is a knot at a angle that is already starting to crack. This could break and is defiantly a safety problem.

2 x 12 Tread Shrinkage
2 x 12 Stair Tread Bracket