Hospital staff at Montefiore Medical Center is among many nationwide worried about a shortage of protective masks that could leave medical workers exposed as coronavirus cases increase.

Michelle Gonazalez says she and her colleagues are in good health, but it's their families they're worried about. Gonzalez lives with her elderly grandmother, someone who would be vulnerable to COVID-19.

There are some N95 masks left, which are more effective than surgical masks, but she says workers directly caring for patients are being told to wipe off and reuse them - guidelines coming from the CDC.

"For us as health care workers, it doesn't seem like science is keeping us safe anymore. I think right now we're demanding the federal government get involved," says Gonzalez. "We've known about this pandemic for three months now. The first cases appeared in January in China. we should have been on top of us and had testing earlier."

Last month, the World Health Organization said airborne spread was not reported for COVID-19, but a new study shows the virus stayed in the air for three hours in certain settings.

Recently, the WHO said it is considering airborne precautions for medical staff.