Breathe in. Breathe out. The purity of the air we breathe is an ever-changing target, as toxins are emitted into the environment, corporations test chemicals, and the environment degrades. Those of us living in Michigan depend not only on federal standards to protect our air quality, but on evolving state standards of industry and nature, and for agencies to stay current on all of changes and to provide permits and to communicate them to the appropriate parties in a timely fashion.
Michigan’s Department of Environment, Great Lakes and Energy (EGLE) is gearing up for a productive 2023. After years of being criticized for underfunding the state agency charged with protecting the state’s air, water, land and other natural resources, the state legislature on July 1, 2022, approved a bipartisan budget for the fiscal year that began October 1, 2022, slating $729 million for EGLE. That’s a 31 percent increase over last year’s budget, and the increased funding allows EGLE to hire 53 new full-time employees.
That’s good news for EGLE’s Air Quality Division (AQD), which has been allocated $4.4 million and the go-ahead to hire 15 employees within its ranks for air quality permitting. Among the many tasks and departments of AQD include emissions monitoring, modeling and reporting, enforcing compliance of state and federal air regulations as outlined within the Environmental Protection Agency’s (EPA) Clean Air Act, lies a tiny group of four toxicologists who make up the Toxics Unit.
The Toxics Unit, assigned the task of regulating sources of air pollutants to protect human health, is charged with creating and updating heath-based screening levels of hundreds of chemicals which are utilized by thousands of businesses in the state that operate within the AQD’s permits to install regulatory programs for the assessment of toxic air contaminant emissions. It is the Toxics Unit’s task to maintain, update and monitor an ever-growing database of what is known as the List of Screening Levels. Created in 1988, the List of Screening Levels now stands at 1,269 toxic air contaminants. The unit in 2021 added 26 new screening levels to the list as they relate to human health exposure risks.
The open-ended list is readily available on EGLE’s website. Chemicals under review for consideration of altering screening levels are also up for public comment. In the early years of the screening program, memos describing the justification for the screening levels were only available upon request. While the public always had the ability to informally comment on the screening levels, as of December 2016, to provide further transparency, the division formalized the comment process and provides a 30-day formal public comment period on all health-based screening levels and their justifications.
Toxicologists develop screening levels by reviewing existing toxicology literature and evaluating health-based limits published by other environmental agencies to create screening levels which are the most appropriate and defensible values. The division prefers large human studies of sensitive toxicology endpoints over animal tests.