FARMINGTON, Maine (AP) — Another firefighter injured in a propane explosion in Farmington, Maine, has been released from the hospital.

Officials announced Thursday that Capt. Timothy Hardy was released from Maine Medical Center in Portland. That leaves four people hospitalized in Portland and Boston, with three of them in critical condition.

The blast at LEAP Inc. killed a firefighter, Capt. Michael Bell, and injured eight other people on Monday.

The explosion remains under investigation.

Meanwhile, the nonprofit is relocating. Western Maine Development Group is allowing LEAP to use a former Barclay's call center in Wilton.

There is available space after the call center closed earlier in the year with a loss of more than 200 jobs.