What industry is the primary user of perchloroethylene, a chemical that researchers at boston university have linked to mental illness, like bipolar disorder?

The dry-cleaning industry, particularly in America, has been the primary user of the industrial solvent perchloroethylene. Garments and other clothing are soaked in the solvent during dry cleaning. The solvent has been re-evaluated severally,like by researchers from the University of Boston linking it to the bipolar disorder, a mental disorder that causes periods of depression and elevated mood.

The answer is Dry Cleaners industry
The solvents that is used in making dry cleaners could affect the part of our brain that controls emotion and memories.
When this part of brain is damaged, there is a chance where we could no longer control our mood, which leads to the bipolar disorder