In a proposal approved for consideration today, the Federal Communications Commission said it will move to require wireless carriers to more accurately track 911 calls indoors.

For years, the FCC has been considering how best to require companies to track calls during an emergency. The newest plan focuses on vertical location information: carriers would need to track the altitude of a caller’s device to within three meters. The plan, the FCC says, will allow first responders to better locate callers in busy metropolitan areas, where they may need to find someone in a multi-story building. Carriers would have to meet the requirement for 80 percent of indoor 911 calls, starting with the biggest cities.

The proposal would go into effect in 2021

“The FCC is committed to ensuring that when you call 911, you will get the help you need,” Chairman Ajit Pai said in a statement. The plan will receive a full vote at a later meeting, and would go into effect in 2021.

The proposal did not come devoid of controversy. The consumer advocates at Public Knowledge questioned whether the plan adequately protects sensitive information, but said today that their concerns were addressed.

Commissioner Jessica Rosenworcel, one of two Democrats on the five-member commission, voted against the plan, arguing that it’s still insufficient. “I don’t think this is ambitious enough,” she said in a statement. “In the years since this framework was put in place, technology has evolved. It has improved. Our record reflects it is possible to locate 911 callers with more precision — and I think we should be able to do it in less time all across the country.”