Lebanese pagers explosions: What is a pager, how it works and reasons why it may explode

A series of explosion of pagers in Lebanon resulted in at least nine fatalities, injuring over 2,700. The blasts occurred on Tuesday (Sep 17) in Beirut's southern suburbs and other areas. In a statement, Hezbollah said that at 3:30 pm (1230 GMT) pagers used by people working for the group’s institutions began exploding “mysteriously.”A senior Lebanese security source claimed that Israel’s Mossad spy agency planted explosives inside these pagers or “beepers” that were ordered months before the blasts.Taiwan's Gold Apollo has refused that it did not make the pagers used in the detonations. Instead, they had been manufactured by a company called BAC which has a licence to use its brand, the company said.

A pager is a radio-operated electronic device used for transmitting brief text messages. The device is usually designed to only receive messages, but in some cases can also be used to to send messages. When a pager beeps with a new message, the recipient needs to locate a nearby public or landline phone to respond to the message.
Pagers were widely used in the pre-mobile era during the late 1990s. It was a critical communication tool for doctors, journalists and emergency health service providers.
There are several types of pagers - numeric, alphanumeric and use case. A numeric pager, as the name suggests, can only display numbers. It is the simplest and easiest pager to use. Alphanumeric, on the other hand, can display both numbers and alphabets. While a use case pager is specially designed for quick alerts and contact information, particularly in professions that require immediate communication.

One of the major benefits of using a pager or a beeper is the connectivity range. As a pager works on radio frequencies, it can provide network coverage in remote areas as well. Another benefit is that the pagers are difficult to track - a key reason why Hezabollah was using it. Since a pager is usually meant to only receive a message, it is difficult to trace.
Also, compared to mobile phones, pagers offer longer battery life and durability. Also, they are straightforward to use, compared to a mobile phone.

While the exact reason is not known yet, reports suggest that overheating of lithium batteries could be a possible reason behind the detonation. Commonly used in consumer electronics like mobile phones, laptops and electric vehicles, lithium batteries can burn at temperatures near or above 1,100 degrees Fahrenheit (590 degrees Celsius).
A Hezbollah anonymously told news agency AP that the explosions were the result of a “security operation targeting the devices.” The official claimed that “the enemy (Israel) is behind this security incident.”