Facebook launches 'Safety Check' tool to notify friends you are OK during disasters

Facebook Inc. is launching a tool that lets users notify friends and family that they are safe during or after natural disasters.

The tool, called "Safety Check," will be available worldwide to the social network's 1.32 billion users on computers and mobile devices. This includes the basic "feature" phones many people still use to access Facebook, especially in developing countries.

People already use Facebook to tell people they are OK after earthquakes and other disasters but Facebook says the Safety Check tool will make it easier. It grew out of a disaster message board that Facebook engineers created in 2011 following the earthquake and tsunami in Japan.

Once users activate the tool, it will determine their location using the city they have listed in their profile, the last location they've shared or the city where they are using the Internet. If they are in an area affected by a natural disaster, Safety Check will send them a notification asking if they're safe.

If they say yes, their Facebook friends will be notified. There's no option to say no. Users can also mark their friends as safe, but the friends have to approve it.