FLAGSTAFF, Ariz. — Federal regulators approved major changes Thursday to a program that discounts phone service for low-income residents on tribal land.

About 12.5 million people nationwide use Lifeline, a program created more than 30 years ago to improve access to phone service. It gives subscribers a $9.25 monthly discount. About 500,000 of those subscribers on tribal lands get an extra $25 off per month.

Three of the five Federal Communications Commission members said three changes that apply to tribal lands will help reduce waste, fraud and abuse, and expand communications networks that lag behind the rest of the country.

The two commissioners who voted no say the changes won’t improve the lives of the most impoverished and vulnerable residents.

Here’s a look at the program and upcoming changes:

WHAT IS LIFELINE?

The program started in 1985 when landline phones were in most households. Mobile service was added in 2005, and broadband in 2016. Subscribers can get either landline or mobile service, not both.

Lifeline doesn’t give out free phones, but the roughly 2,000 service providers in the program often do.

Telecommunications companies pay into a fund to cover Lifeline, and that cost often gets passed on to customers. A single person making about $16,000 a year alone or about $33,000 for a family of four, or who participates in certain government assistance programs, qualifies.

Government reports show Lifeline provided subsidies of $1.5 billion in 2016.

WHAT’S THE PROBLEM?

The FCC says the Lifeline program is in serious need of reform to cut down on waste, fraud and abuse. Federal investigators earlier this year reported they couldn’t verify whether 1.2 million people who were signed up were eligible. The U.S. Government Accountability Office also found nearly 6,400 dead people had re-enrolled. Last year, the FCC issued a $2 million fine to a wireless company in Hawaii that improperly registered thousands of people for the enhanced tribal subsidy.

Consumer advocates say the GAO’s sample size was too small to apply to the whole program. They also say the report doesn’t accurately characterize the program because it doesn’t reflect some new reforms. They want the FCC to focus on expanding the program to people who are eligible and haven’t signed up.

WHAT IS CHANGING?

The changes will drop the deeper tribal discount for phone providers that don’t maintain their own networks and piggyback off existing infrastructure. The FCC also is considering limiting the program to those facilities-based providers nationwide.

The FCC says resellers have no incentive to expand communications networks on tribal land because they don’t own them. Many people still live without electricity, running water and phone service on reservations.

People like Joe Redcloud of the Oglala Sioux Tribe in South Dakota say eliminating resellers will give Native Americans fewer or no options for mobile service. “This will be a travesty to Indian Country because it will turn back the clock to times when consumers had but one choice,” he said this week.

The FCC also will redefine tribal lands. Right now, cities like Reno, Nevada, and Oklahoma City are included in tribal areas.

The third change will require independent verification of tribal residency.

The changes won’t go into effect for at least 90 days.