Eighty-five-year-old technology is still one of the best ways for government officials to convey information to the public during natural disasters. FM radio, first introduced in the 1930s, remains a critical communication channel during emergencies, and smartphone manufacturers can provide this lifeline to their customers at little cost.

Despite the popularity of smartphones, the cellular networks on which they rely to talk, text, and access the Internet are vulnerable during hurricanes, floods, tornadoes, wildfires, and other natural disasters. Even when towers are not damaged or destroyed, the surge in call volume during an emergency often creates network congestion that makes communication difficult or impossible.

But storms that disable cell towers are unlikely to knock out every local radio station in an area, most of which have backup generators in case the power goes out.

For this reason, FM radio stations around the country have partnered with disaster relief agencies to disseminate vital evacuation instructions, weather updates, and other information to communities during crises. When cellular networks go dark, FM radio stations may be the only means of communicating lifesaving information.

The value of FM radio has been demonstrated again and again. When Hurricane Isaac made landfall in 2012, most of New Orleans was without power for three to five days. Across the city, cell phone service didn’t work, power outages prevented access to TV, and internet connectivity was unreliable or non-existent. During that time, local radio stations broadcasted 24 hours a day, providing critical information and comfort to the city’s residents. Without the lifeline that radio communications provided, confusion and chaos would have been greatly exacerbated.

After hurricanes Irma and Maria left 91 percent of Puerto Ricans without cellular coverage last year, many turned to radios for emergency information.

But millions of American households do not own a battery-powered FM radio, potentially jeopardizing their safety in a crisis. Research by the Centers for Disease Control in 2012 revealed that nearly one-quarter of American households did not have a working battery-operated radio.

Luckily, most smartphones already have FM antennas pre-installed. Pew Research Center found that 84 percent of households in the U.S. had at least one smartphone in 2016 — a proportion which has likely increased since then.

Most smartphone users can access FM radio signals by downloading a simple app; no additional equipment is needed. Unfortunately, not all smartphone manufacturers have activated the FM chips inside their phones, depriving their customers of this potentially lifesaving feature.

That is why Craig Fugate, former head of the Federal Emergency Management Agency, has urged smartphone manufacturers to make these capabilities accessible to their during times of emergency. In addition, Federal Communications Commission Chairman Ajit Pai, while citing public safety benefits, has repeatedly called on the wireless industry to activate the FM chips already installed in almost all smartphones sold in the U.S. It is inexplicable why some smartphone manufacturers do not allow this FM functionality.

Enabling FM radio capabilities comes at virtually no cost, either to consumers or the manufacturing industry. Given the benefits, manufacturers who do not already make FM radio available to their customers should strongly consider doing so.

The public safety benefits are clear. When disaster strikes, the ability to access FM radio messages on a smartphone saves lives. As deadly wildfires ravaged California last year, many residents were not aware of the danger until minutes before the flames reached their homes, partly due to malfunctioning cellular alert systems. Had the warnings broadcast by FM radio stations been heard by a greater number of people, more of them would still be alive today.

Manufacturers should do all they can to make this life-saving technology even more widely available to consumers.

Published in Forbes.