Leafgro Safety for Pets: What's in Maryland's Municipal Compost?

Leafgro (Maryland's municipal compost from leaves, grass, land-clearing debris) caused black stools in a dog—raising legitimate safety concerns.

What's in Leafgro

• Fall leaves (municipal collection)
• Grass clippings (often treated with "weed & feed," herbicides)
• Land-clearing debris (wood, dirt, rocks—plus potential contaminants: styrofoam, household chemical runoff)

Documented Risks

USGS/EPA study at Patuxent Wildlife Research Center found residual pesticides and heavy metals in Leafgro and ComPRO. Heavy metals (lead, arsenic, cadmium) cause dark stools in dogs. Herbicide residues (2,4-D, dicamba) persist through composting.

Vet's Advice Was Correct

Keep pets away. Municipal compost is a great waste-diversion step—but not a guaranteed clean product for food gardens or pet areas.

Safer Alternatives

• Home compost (you control inputs)
• Certified organic compost (OMRI-listed)
• Leaf mold (pure decomposed leaves—no grass, no debris)
• Straw, pine needles, wood chips (single-source, traceable)

For lawns: top-dress with your own compost or trusted source. For pets: fence off treated areas until fully incorporated and irrigated.