LANSING, Mich. (Michigan News Source) — Michigan officials are looking to put tighter controls on firewood crossing state lines, warning that a few innocent-looking logs can carry far more than just fuel for a campfire.

The Michigan Department of Agriculture and Rural Development (MDARD) is proposing a new Exterior Firewood Quarantine, warning that untreated logs are one of the easiest ways invasive insects and plant diseases sneak into the state.

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Agency officials say more than 140 known pests and pathogens are capable of traveling undetected inside wood.

If adopted, the rules would require all firewood brought into Michigan—no matter the species or state of origin—to be treated before crossing the border. Acceptable options include heating the wood to an internal temperature of 140 degrees Fahrenheit for at least an hour, along with other approved methods such as steam, microwave, or dielectric heat.

The department is soliciting public feedback through an online survey, with comments due by February 9.

MDARD says the rules would not apply to certain materials, including kiln-dried dimensional lumber, small wood chips, or logs headed directly to industrial processing facilities like sawmills, pulp mills or power plants. Wood that has already been processed into finished products before entering the state would also be exempt.

Firewood that is locally sourced, collected for personal use, or not intended for resale would fall outside the quarantine as well.