A worker monitoring natural gas levels at a Middletown, Conn., power plant reportedly called for an evacuation moments before last week's explosion that killed five workers.

The Hartford Courant, citing witnesses and investigators it did not identify, said the message, radioed throughout the Kleen Energy plant, warned workers that gas meter readings had spiked.

SLIDESHOW: Deadly Connecticut Power Plant Explosion

The newspaper reported Wednesday that investigators have recovered the two gas meters used at the time of the explosion, which occurred while workers were purging gas lines at the plant, which was under construction.

Investigators said they hope to recover memory chips that could allow them to determine the gas levels before the explosion.