NEW MEMPHIS, Ill. (KMOX) – Residents of New Memphis, Illinois can breathe easy this morning — now that crews have capped off a pair of leaking anhydrous ammonia tanks.

A voluntary evacuation notice was in place for about 20 homes overnight, after a farmer towing the tanks into a field off Illinois Highway 160 north Illinois Highway 177 split discovered the leak.

Emergency officials concerned about the gas cloud let residents know of the potential danger and advised them to shut their windows, but there was no mandatory order to leave.

The leak was contained around 2:30 a.m. Wednesday, but not before two firefighters assisting in the effort were overcome by fumes and were treated and released at an area hospital. No word yet on what caused the tank to spring the leak.