“When discharging industrial gas into the indoor environment in high altitude astronomy, we never wore breathing respirators that fed us oxygenated air at above the legally required 19.5% oxygen levels.” — Steven Magee Copy Share Image
“When discharging industrial gas into the indoor environment in high altitude astronomy, we never wore protective breathing respirators that fed us oxygenated air at above the legally required 19.5% oxygen levels.” — Steven Magee Copy Share Image
