People are wearing this mask when their lungs are constricted because of asthma attacks or pneumonia.
And when they do get a flu, they are using it as a nasal spray.
A new study by researchers at Boston University and Boston Children’s Hospital has found that the masks can actually kill people when they use them improperly.
The study, published in the journal Clinical Toxicology, found that people using these masks while wearing an oxygen mask are up to 70 percent more likely to die.
They found that when people use the mask improperly, they inhale more air and lose the oxygen that the mask provides.
They also lost about 20 percent of the oxygen they breathe in while using a mask, compared to the maskers who were using it correctly.
The masks also make breathing more difficult.
They make breathing easier for some people by blocking their airways, but for others, it makes breathing harder because they can feel a strong resistance to breathing.
The study, funded by the National Institutes of Health, analyzed data from more than 13,000 patients who had used masks for at least three months.
Researchers used oxygen masks and other mask products for more than 5,000 people, but the masks they used weren’t necessarily the same masks used for those studies.
The researchers found that oxygen masks were associated with significantly more deaths when used incorrectly.
They said the masks were a cause of death for patients who were experiencing symptoms of asthma or pneumonia and who had difficulty breathing.
This is an update on an earlier story.