Respirator Protection Devices and Methods to Detect and Remove Toxic Gases from the Air - Cobinamide Encapsulated Silica-based Materials for Respirator Canisters

A respirator protects the wearer from inhaling dangerous substances, such as chemicals and infectious particles. CDC developed devices and methods to detect and remove chemicals such as hydrogen cyanide, cyanogen, hydrogen sulfide, nitrite, and nitric oxide from the air for those wearing respirators. Cobinamide (a Vitamin B12 analog with a high affinity to cyanide) molecules are immobilized within a silica matrix that allows for the infiltration and containment of gaseous chemicals. Since the chemical(s) bind to the cobinamide, such material is embedded into respirator canisters to help facilitate the removal of toxic molecules from the air.

The chemical(s) binding to the cobinamide also result in a color change that can be analyzed qualitatively or quantitatively. The cobinamide-loaded silica matrix can be incorporated into a respirator canister (such as a canister designed to protect workers against chemical, biological, radiological and nuclear weapons (CBRN)) to act as an end-of-service-life indicator (ESLI) alerting when to change equipment. Different absorbance of the cobinamide/silica composite within the respirator canister can be monitored, and the device can be configured to trigger a visual and/or audible alarm once a particular concentration of the chemical(s) meets a certain threshold, indicating that the canister needs to be replaced. Current ESLI technology only depends on the user to monitor a color change via a colorimetric indicator, viewed through a clear box on the outside of the gas mask canister. This is an issue for color-blind persons, those in low-light settings, and users if they are preoccupied and unable to continuously monitor the indicator. The CDC/NIOSH technology can be configured for both a visual and/or audible alarm.