I use an extracted at night that is pump into my BIPAP machine (I have central sleep apnea). This odor is harsh and appears to leave a deposit in my nasal cavities as I can smell it all day long. I use a saline nasal flush twice a day and that is not removing the odor. I hope it is not toxic. I complain to the company that supplies the machine and they gave me a replacement. This time it still had the odor but much less. I note that oxygen supplies at the hospital has no such odor. I hope that the help for my COPD is not doing additional harm.