Fill $f(x,y,z)=xy+x'z$ in K-map
Hazard occurred because a variable and its complement passed through different number of logic operations.
In other words, if a variable and its complement are present in different product terms, may cause Hazards.
Here it is variable $x$, that may cause Hazard.
So make an extra pair in K-map that doesn't contain variable $x$.
so $f(x,y,z)=xy+x'z +yz$ is Hazard Free.
but we still have x and x' in expression.