Prior to the early twentieth century, a worker who was injured on the job could collect damages only by suing his employer. To sue successfully, the worker-or his family, if the worker had been killed-had to show that the injury was due to the employer's negligence, that the worker did not know the job was hazardous, and that the worker's own negligence had not contributed to the accident. These lawsuits were difficult for workers to win, and even workers who had been seriously injured on the job often were unable to collect any damages from their employers. Beginning in 1910, most states passed workers' compensation laws that required employers to purchase insurance that would compensate workers for injuries suffered on the job. A study by Price Fishback of the University of Arizona and Shawn Kantor of the University of California, Merced, shows that after the passage of workers' compensation laws, wages received by workers in the coal and lumber industries fell. Briefly explain why passage of workers' compensation laws would lead to a fall in wages in some industries.