WATCH: Don’t use face masks with valves!

MANILA, Philippines — Health officials warned against using valve-type masks to protect from COVID-19.

These are masks with exhaust valves designed for industrial use and not for medical or surgical purposes.

Worn by carpenters and other workers to prevent inhaling dust and other particles, masks with exhaust valves don't offer "two-way" protection, said Food and Drug Administration (FDA) Director General Eric Domingo.

“They do not have infection control (mechanism). The valves are not designed to, for instance, protect a person from inhaling the air being exhaled by an infected person wearing it,” Domingo said in a radio interview.

“The protection that we want from a mask is two-way. If you are sick, you will not infect others and at the same time, if you are well, you will not get the infection from other infected individuals.”

World Health Organization said that while disposable respirators with exhalation valves are lightweight and fairly comfortable to wear, they can’t be used when working in a sterile area since the valve allows droplets and particles exhaled by the wearer to escape.

The Medical City has issued an advisory against wearing masks with exhaust valves inside its clinic premises.

“While masks with valves are designed to ease exhalation and decrease humidity for the wearer, they do not block transmission of COVID-19 because they allow exhaled air and droplets to escape.”