Decades of industrial activity in Pittsburgh have left behind numerous brownfields—abandoned or underused properties where past industrial operations have caused environmental contamination. These sites, once centers of heavy manufacturing like steel production, are now being redeveloped into modern research centers, technology hubs, and residential areas. However, beneath the surface of these sites, a hidden world of microorganisms has thrived, evolving to survive and, in some cases, break down the pollutants left behind. One such site is Hazelwood Green, a former steel production area along the Monongahela River. This location is heavily contaminated with petroleum hydrocarbons, heavy metals, and other toxic substances, including benzene, toluene, ethylbenzene, and xylene—collectively known as BTEX. These chemicals are harmful to human health and the environment, with some classified as carcinogens. Despite the contamination, the soil is teeming with life, hosting billions of microorganisms that have adapted to these harsh conditions. Researchers at Carnegie Mellon University are studying these microbial communities to understand how they have evolved in response to pollution. Using techniques like soil core sampling and metagenomic sequencing, scientists are identifying the types of microorganisms present and their potential to break down pollutants. By comparing historical contamination records with current microbial data, they aim to determine how past pollution has shaped the ecosystem over time. To assess the microbes' ability to clean up contaminants, scientists isolate bacteria from the site and other locations in Pittsburgh and test whether they can use pollutants as a carbon source. This process helps identify which bacteria are most effective at breaking down specific contaminants, potentially aiding in bioremediation efforts. The research also involves collaboration with CMU’s AI Science Foundry, where robotic systems enable the simultaneous screening of thousands of bacterial species. Open-source tools are being developed to analyze bacterial genomes and identify genes linked to pollution degradation. Bioremediation—the use of microorganisms to clean up environmental pollutants—is already used in various applications, such as cleaning up oil spills and treating wastewater. However, finding microbes that can effectively break down specific contaminants under the unique conditions of a polluted site remains a challenge. By studying microbes that have already adapted to these environments, researchers may improve existing bioremediation techniques. As Pittsburgh and other industrial regions of the Rust Belt undergo transformation, the biological solutions to environmental cleanup may have been evolving beneath the surface for decades, waiting to be discovered.