A company in Louisville’s Rubbertown neighborhood wants to change the chemicals it uses in the production of synthetic rubber. The Air Pollution Control District held a public hearing on the request today.American Synthetic Rubberuses a solvent called toluene to produce rubber, and toluene is regulated as a category 2 toxic substance under the city’s Strategic Toxic Air Reduction program. ASR wants to stop using it, and substitute cyclohexane and methyl cyclohexane in the processes.Chief Operating Officer Brad Karas says the company wants to switch chemicals because it will help make higher-performance tires.“We candidly acknowledge that we would not make a change in solvent if it were not to be improving our competitiveness since emissions of tolunene by us are already considered to be de minimus under STAR,” he said.But also:“Cyclohexane, methocyclohexane poses less of a risk to human health than toluene.”A toxicology expert testified on behalf of the company, saying the new chemicals are safer than toluene. Dr. Cham Dallas of the University of Georgia cited studies showing only concentrations much higher than those being planned at the plant cause health issues such as headaches and dizziness.But that didn’t reassure Eboni Cochran of Rubbertown Emergency ACTtion. She says regardless of laboratory studies of cyclohexane and methyl cyclohexane, she worries there’s no research into the cumulative effects of the chemicals people in her neighborhood are breathing.“You’re talking about one chemical or two chemicals,” she said. “We’re bombarded with chemicals—multiple chemicals. Maybe a small amount of this chemical in conjunction with even two or three other chemicals, that could cause central nervous system issues as well.”Now, the Air Pollution Control District will decide whether to grant the permit.