State and federal crews are making progress cleaning up homes contaminated by the old Black Leaf Chemical plant in Louisville’s Park Hill neighborhood.The Black Leaf plant was home to many companies during the 20th century, including several that produced pesticides. In 2011, high levels of heavy metals and pesticides were discovered in the site’s soil. Later, residential testing revealed the dangerous chemicals had migrated to nearby homes.Since cleanup began in August, crews from the federal Environmental Protection Agency and State Division for Environmental Protection have remediated 54 properties by excavating the soil and replacing it with fresh soil. They’ve gotten permission to clean up 15 more homes, and hope to complete that work by the end of the year.At the same time, the commonwealth is in negotiations with the companies that have occupied the property in the past. They hope to develop a plan to clean up the Black Leaf plant itself by the end of this year.