St. Louis County, MO Fire Regulations: Outdoor Burning (2026)

' Everything else in the section exists only as a carve-out from that blanket rule, and the code is explicit that any open burning not specifically exempted stays illegal unless the Director of the Air Pollution Control Program approves it in advance. The listed exceptions each carry their own numeric limits: recreational fires must use only untreated, seasoned dry firewood free of yard waste or treated wood, with a cumulative base area capped at nine square feet and no smoke or ash visible beyond the property line; food-preparation and barbecue fires face the same nine-square-foot cap and fuel restriction unless the fire is contained in built equipment such as a grill or rotisserie; yard-waste burning is allowed only on lots of three acres or more (no minimum near the Meramec, Missouri, or Mississippi Rivers), only between September 15 and April 14, and only up to a sixteen-square-foot base area; and natural-resource conservation burns need either a Missouri Department of Conservation burn plan or Air Pollution Control Program approval.

Fire-training burns of actual structures need prior program approval, while training at a designated academy does not. Commercial land clearing must follow the state Air Conservation Commission's open burning rule, get prior program approval, and run an air curtain incinerator at all times. 390: up to $1,000, up to a year in jail, or both, with each day of continued burning a separate offense.