Healthcare workers are being diagnosed with cancers that occupational-health specialists say could be linked to exposure to chemotherapy agents and other toxic powerful drugs that have saved hundreds of thousands of patient lives. An InvestigateWest investigation has found that the federal Occupational Safety and Health Association does not regulate exposure to these toxins in the workplace, despite multiple studies documenting ongoing contamination and exposures. Studies as far back as the 1970s have linked increased rates of certain cancers to nurses and physicians. Occupational-health experts believe that's because when nurses, pharmacists, technicians and, increasingly, even veterinarians mix and deliver the drugs, accidental spills, sprays and punctures put them in close, frequent contact with hazardous drugs.