Burning solid wood produces sparks, shifting embers, and creosote, a flammable liquid that can accumulate in and clog vents and chimney stacks. Wood can also ferry things like mold and mildew into the home, and stacked logs can shelter spiders, termites, insects, and even rodents. There’s also the risk of fire and carbon-monoxide poisoning, so be sure to install and regularly test smoke and carbon-monoxide alarms.