Michigan lawmakers raise concerns over biodegradable materials in Great Lakes erosion control bill

The Michigan Legislature convened on June 4, 2025, to discuss critical issues surrounding natural resources and tourism, with a particular focus on proposed legislation concerning construction materials for erosion control along the Great Lakes.

One of the primary concerns raised during the meeting was the allowance of above-grade walls constructed from movable brick, biodegradable materials, and soft permeable synthetic textiles, specifically polypropylene and polyester. Critics highlighted that the term "biodegradable material" remains undefined within the bill, raising alarms about the potential environmental impact of these materials.

Experts pointed out that many biodegradable plastics do not fully decompose but instead fragment into microplastics and nanoplastics, which pose significant threats to the Great Lakes ecosystem. With Michigan's extensive shoreline of over 3,000 miles, the responsibility to mitigate plastic pollution was emphasized. The discussion underscored that polypropylene and polyester are prevalent in consumer products and erosion control materials, contributing to microplastic pollution detected in various surveys of the Great Lakes.

The meeting also addressed the health implications of microplastics, which can enter the human body and potentially cause inflammation, disrupt immune systems, and carry harmful chemicals. The presence of these materials in breast milk and their ability to enter the bloodstream were particularly alarming points raised by health advocates.

Additionally, the proposed bill would permit the construction of soft erosion control structures without a permit, provided they do not impede walkability and are reported to the Michigan Department of Environment, Great Lakes, and Energy (EGLE). However, concerns were voiced about the long-term environmental impact of such structures, especially if they are made from undefined biodegradable materials or plastics that do not degrade naturally in Michigan's shoreline conditions.

The discussion concluded with a call for clearer definitions and stricter regulations regarding the materials used in construction along the Great Lakes, emphasizing the need for responsible stewardship of Michigan's natural resources to protect both the environment and public health.