Firefighters had to remind three downtown residents Tuesday night of the city’s burning ordinance after they responded to reports of a large fire in a backyard, according to a release. Crews were sent around 11:30 p.m. to the 100 block of Lathrop Street for reports of a large fire in a backyard, officials said. Firefighters were initially told by the people attending the fire that they were burning a large piece of wood, but once crews got closer, they admitted they were burning a box spring mattress, according to the release.