LYNN – An early morning two-alarm fire has left 11 people homeless who lived in a multi-family, three-story home at 10 Endicott St.Acting Fire Chief James Carritte said the fire may have begun in the basement but that firefighters found fire on all three floors.”The firefighters were able to open up the walls on each of the floors and opened the roof in the rear of the building and really did a great job,” Carritte said. “We were lucky in the fact this was a morning fire and not one at night. We also heard smoke alarms going off when we entered the building and that helped in alerting residents. This is a classic example of how smoke detectors save lives.”Second-floor resident Ileana Holquin rushed 5-year-old son Brian and daughter Naigella, 8, out of the building after smelling natural gas.”Smoke was coming out of the heater vents,” she said.Holquin’s sister, Sheyla, lives in the third-floor apartment with three family members.”We smelled gas. At first we thought it was the heating system,” she said.Holquin family members plan to stay with their brother, Ruben, in Peabody while first-floor tenant Jose Chavez and three family members will go to a hotel.For the second time in as many weeks, local police officers played a key role at a fire scene. Officers Paul Cotter and Edward Monahan ran into 10 Endicott, alerted residents and helped them get out. Police Lt. William Sharpe said Cotter and Monahan were taken to Union Hospital for “precautionary reasons as they were exhibiting some signs of smoke inhalation. The officers are expected to be treated and released.”The pair were on patrol around the corner from Endicott Street when they heard the 911 emergency fire call. They saw residents coming out of the building as they moved down the first-floor hallway and upstairs to the upper floors.Monahan stopped at the second-floor apartment to help the Holquins get out of the building while Cotter continued up the stairs.”As I reached the third floor I encountered more choking thick black smoke making it very difficult to breathe,” Cotter wrote in his report.He caught his breath on the third-floor porch before pushing his way into thick smoke filling the third-floor apartment and aiming his flashlight into the apartment’s rooms. He caught another breath on the porch and prepared to push back into the apartment when residents outside the building told him it was empty.District Chief Lee Oliver said an initial investigation indicated the fire started in the basement near the oil-fired, forced hot air heating system.”We’re looking at it as an accidental fire,” Oliver said.He said the fire ascended up the building’s center from the basement to the roof. Fast work by the large number of firefighters who converged on the fire contained it to the building’s core. Oliver said the building needs extensive renovation but is structurally sound.Oliver said firefighters found no traces of natural gas or any indication of leaking fuel oil.City records list 8-10 Endicott’s owner as Nguyen Chinh Van of Malden. He bought the building in 2008.Carritte said the first alarm came in at 7:04 a.m., it was deemed a working fire at 7:08 a.m. and the second alarm was sounded at 7:13 a.m.Carritte said the majority of those tenants left homeless by the fire were making plans to stay with family or friends.Two Lynn ladders, a ladder from Swampscott and six Lynn engines were used battling the fire.