Which raises the question; why haven't employers provided these tools already? The initial investment? (which could be substantial)
According to the LA Times article on the same topic today (page B1), CA banned the short-handled (12") hoe in 1975, since using it to pull weeds was hard work and since anyone resting would be immediately visible.
So, the farmers/subcontractors hired workers to pull weeds by hand. Still, farmers prefer other methods, since hand-weeding is slow and labor-intensive (read: expensive).