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But the ranks of those who have became symbols for increased safety include pharmacists Bruce Harrison, of St. Louis, and Karen Lewis, of Baltimore; veterinarian Brett Cordes, of Scottsdale, Ariz.; and nurse Sally Giles, of Vancouver, B.C.

Like Crump, all of them eventually got cancer, or in Lewis' case, a precancerous condition. Cordes was diagnosed four years ago at age 35. Giles was in her 40s, and Lewis and Harrison were in their 50s when diagnosed. All but Lewis and Cordes are now dead.

Early exposure

On an afternoon in May of 2009, Crump sat in a coffee shop near her Redmond home and perused a list of chemo drugs now deemed hazardous for health-care workers to handle. She runs her fingers down the page. It's a long list: cyclophosphamide, doxorubicin, fluorouracil, methotrexate. And the list went on.

"Yeah, I worked with all of them," she said. Crump started at Swedish Medical Center in the early 1980s, before pharmacists used special protective "hoods" over countertops to contain spray and chemo contamination. They didn't use gowns or gloves.

They had no reason to think they should. Occasionally, drugs would spill on the countertops.

"We would wipe it off and throw (the towels) in the garbage," she said.

Most of the chemo came in vials and would be transferred into plastic IV bags. Sometimes there would be spray when they punctured the vials. Other drugs came in ampuls, glass vessels sized for a single infusion. "I'd file the neck of it, then snap real fast," she said. "A lot of times, I got cuts."

"But the feeling at the time was — whatever little vapors or splash — it was such a low exposure through the skin, it was insignificant."

That was a common attitude then — and now, said Dr. Melissa McDiarmid, director of occupational health at University of Maryland.

"So many people think: It's just a 'little bit.' They don't understand it's a little bit of something designed to be toxic and to be highly absorbed biologically."

Still, Crump wondered whether those early, ongoing exposures had contributed to the cancers she and her peers have gotten. She first recalled getting alarmed after a pharmacy tech — someone with whom she mixed a lot of chemo — died at age 29 of a brain tumor. Around the same time, several colleagues experienced miscarriages.

Since that time, a number of studies have shown an association between exposure to chemo agents and adverse reproductive effects including miscarriage, birth defects and low birth weights.

A 2005 survey of 7,500 nurses, reported in the journal Oncology Nursing Society, found significant associations with infertility and miscarriage in nurses who handled chemo before the age of 25.

Nurses, who occasionally spill the chemo drugs on their clothing or splash it on their skin, had a greater chance of premature labor if they administered nine or more doses of chemo per day. The survey also found that nurses who didn't use gloves as often while preparing chemo were more likely to have children with learning disabilities.

"Now all these people about my age are getting cancer — cervical, ovarian, prostate, endometrial, brain," Crump said. "All of us, at one time or another, worked with chemo — we wondered, well, is there a connection?"

In addition, chemo drugs have found wider application in the treatment of arthritis, multiple sclerosis and other diseases. For example, methotrexate is used to treat autoimmune diseases such as arthritis, and azathioprine and mitoxantrone are used to treat multiple sclerosis.

Chemo is poison, by design. It's descended from deadly mustard gas first used against soldiers in World War I.