Each day, employment-related injuries and workplace violence cause the deaths of more than 17 workers and the injuries of hundreds of workers. Other workers suffer and sometimes die from occupational illnesses resulting from toxic exposures, stress, and abuse at the workplace. State and local prosecutors are increasingly investigating, indicting, and convicting companies and their executives, in appropriate circumstances, for workplace safety violations through their authority under the statutory and common criminal laws of their jurisdictions. The modern era of criminal law enforcement in the workplace began in 1985 with an Illinois prosecution for involuntary manslaughter after a worker died following exposure to cyanide poisoning at a silver reclamation facility. Five elements of common-law workplace offenses in Massachusetts and other States apply to these cases. However, the law is still open to argument. In addition, fact patterns are often complicated, investigation and preparation of cases are difficult, and significant resources are required. Nevertheless, prosecutorial action is justified and necessary in specific circumstances. Prosecutors must responsibly use their discretion and must articulate and apply consistent standards, especially when emerging or evolving concerns are involved. Photographs and reference notes