Throw a large amount of baking soda or sand onto the fire. Spray the fire with a fire extinguisher if the dry ingredients don't stop it.
Cover the fire with a metal container, such as a cookie sheet or a trash can lid. Remember to use an oven mitt or tightly wrap a towel around your arm before placing the metal lid on the fire. This will protect your arm from the flames and even from the intense heat.
Close the doors to the fireplace. This will take away the fire's oxygen supply.
Get everyone out of the house.
Call 9-1-1.
Spray the roof with a hose once outside. This will help prevent the spread of the fire.