Photo by JEFFREY HASTINGS A pair of extension ladders are strewn in the yard of the Mt. Pleasant Street home in Derry where two men suffered severe electrical shock when the ladders came in contact with power lines. (Photo by JEFFREY HASTINGS)

DERRY — Two roofers working at a residence at 3 Mt. Pleasant St. were flown to Boston hospitals in critical condition, officials said, after the extension ladders they were using came in contact with overhead power lines.

Both men, who haven’t been identified, went into cardiac arrest at the scene, according to battalion Chief Scott Haggart. He said an engine, an ambulance and a paramedic were initially dispatched to the scene, but when it was learned there were two victims, another ambulance and a second engine, along with Haggart, responded to the scene.

The men were working at the one and a half story New Englander style house, which is near the intersection of Route 102 and Mt. Pleasant St.

Haggart said one of the men was transported directly to the helipad at Parkland Medical Center, then transferred to a Boston Med Flight helicopter and transported to Massachusetts General Hospital.

The other man received treatment at Parkland before he was transferred, also by Boston Med Flight, to Brigham and Womens Hospital.

Photo by JEFFREY HASTINGS A police officer speaks with an Eversource lineman in front of the Derry house where two men were electrocuted when the ladders they were using contacted power lines. (Photo by JEFFREY HASTINGS)

An investigation is underway by local officials, as well as by representatives of the Occupational Safety and Health Administration (OSHA).

Haggart cautioned anyone using a ladder to “always look up before raising the ladder, and keep all ladders at least 10 feet away from power lines.

Dean Shalhoup may be reached at 594-1256 or dshalhoup@nashuatelegraph.com.

Photo by JEFFREY HASTINGS Two of the Eversource linemen called to a Derry residence Monday for a report of two men electrocuted arrive at the scene. (Photo by JEFFREY HASTINGS)