Massachusetts lawmakers may pass a ban on the sale of mobile location data, making it the first state in the US to do so.

Location data from mobile devices is a billion-dollar industry, with everyone from marketers to US intelligence agencies buying up such data. Law enforcement often purchases data from data brokers since it provides a legal loophole around the need for a warrant.

According to The Washington Post, the Massachusetts legislature is considering what would amount to a near-total ban on the sale of mobile location data. The bill would also close the loophole for law enforcement by requiring a warrant before agencies could buy such data.

“I have every reason to be optimistic that something will be happening in this session,” said Sen. Cindy Creem, the bill’s sponsor.

If the bill does pass, Massachusetts will be the first state to take such drastic action to protect mobile location data.