Six firefighters and one civilian were injured yesterday in a blaze that took place in the Hamilton Heights section of Manhattan. The fire started around 1 a.m. on the second floor of a building on Amsterdam Avenue near 146th Street and lasted around an hour and a half. Three dozen of the adults and children residing in the building had to evacuate their homes and stay with friends or in nearby motels. One woman feared that the fire had burned down her Christmas tree and all of the gifts she had already purchased this holiday season. All injuries were minor. While the cause of the fire isn't clear, it's a good time to remind everyone that the FDNY recommends the use of UL-approved holiday lights and to never leave lit candles unattended (always extinguish them before going to bed). Also, make sure you have a working fire alarm in your home.