Maine’s telecommunications regulator on Thursday stepped up an examination into ways to keep the 207 area code, which is expected to run out of numbers by 2024, as carriers and others suggested they not preserve it.

The Maine Public Utilities Commission has been looking for ways to preserve the state’s single area code that included potentially releasing blocks of numbers held but not used by telecommunications service providers. But the carriers balked at the idea, with one of them asking for even more numbers for itself, Commissioner R. Bruce Williamson said.

“Generally speaking, the parties support the notion that the easiest and best path forward is not preservation,” Williamson said.

He recommended closing the current inquiry and stepping it up into an investigation. The two other commissioners agreed. The investigation will require carriers to provide the commission with an up-to-date inventory of their number resources and to identify all number blocks. Those blocks are the result of a federal method assigning numbers to companies in 1,000-number blocks, according to the commission.

The state has about 8 million usable telephone numbers, according to the commission. The three digits after the area code, known as the exchange, contain about 10,000 usable phone numbers broken up into 10 blocks of 1,000 numbers each. Those numbers are overseen by a national pooling administrator.

When a telecommunications service provider uses 100 of the numbers in a 1,000-number block, the remaining numbers are reserved for exclusive use of that service provider. The situation leads to unused numbers unavailable to anyone but the carrier, the commission said.

The commission said the actual use of numbers in the 207 area code is 37 percent. In its inquiry, it asked service providers to share their methods for how they forecast the need for additional blocks and whether they had blocks that could be returned to the pool. Verizon responded saying it had one block of 1,000 numbers that it returned to the general pool in April.

In June 2019, the commission petitioned the Federal Communications Commission for the ability to assign numbers to telecommunications service providers on an individual basis rather than in 1,000-number blocks. That petition was submitted in support of an earlier petition from New Hampshire’s regulator, which also is seeking ways to preserve its 603 area code.

Both petitions asked to have numbers assigned individually rather than in blocks and both are among approximately a dozen U.S. states that still have only one area code. Jody McColman, staff attorney for the Maine commission, said there are millions of available numbers in the 207 area code, but they are ineligible for release back into the numbering pool.

“Maine’s 207 area code is a strong part of our state’s identity,” she wrote.