Chemotherapy is a lifesaving cancer treatment, but without adequate federal safety regulations, it is also endangering the lives of health care workers who mix and administer the drug, according to an investigative report by InvestigateWest.

The cell-killing drugs can sometimes spurt out of a vial onto a pharmacist’s skin, or linger on counters and floors even after nurses think they have cleaned up accidental spills. Some health professionals with cancer or pre-cancerous conditions say they have experienced “secondhand chemo” after decades of exposure to the toxic chemicals.

Chemotherapy agents, when dispersed in the air, or onto surfaces, are invisible, difficult to clean, long-lasting, easily spread, and capable of causing genetic damage. They’ve been found on the outsides of the drug vials shipped from manufactures, on floors and countertops, on keyboards, and garbage cans and door knobs.

Few federal regulations exist to ensure that workers are not exposed to chemo, InvestigateWest reports, and an upcoming decade-long U.S. Centers for Disease Control and Prevention study has found that many workplaces are still contaminated. In some instances, chemo even appears in urine samples.

Researchers since the 1970s have observed that doctors and nurses have higher cancer rates than the general population, but drawing a conclusive link between chemo exposure and disease has been difficult because cancer is complex and diverse, and because the damage may not manifest until years later.

Furthermore, the most basic safety protections are not fully in place. The National Institute for Occupational Safety and Health issued an alert in 2004 recommending chemo-resistant gear, respirators, face shields and “closed-system” fume hoods to prevent the chemicals from becoming airborne. The guidelines, however, are voluntary.

Jordan Barab, the deputy assistant secretary of Labor for the Occupational Safety and Health Administration, said that OSHA does not have the resources to develop regulations for workplace drug exposures. There are enforceable limits on  other cancer-causing substances like benzene and asbestos, but not hazardous drugs.

“It’s been a silent threat for a long time with very little attention by the government,” said Bill Borwegen, occupational health and safety director for the Service Employees International Union, the labor union that represents nurses nationally.