My father happens to work as an industrial chemist, and his job is to essentially mix chemicals to make odd agents such as fertilizers for farmlands, medicine, or aerosols.
These chemicals are incredibly dangerous especially when inhaled.
He works on a contract basis and the last dealer that he worked for, had a ductless mini split appliance however had neglected it! As he mixed the chemicals he could easily feel the chemicals settle on the surfaces of the lab even though he had on gloves and a mask. The management had not performed even a single Heating and Air Conditioning repair since it was installed a couple of years back. My father, being experienced, made a deal with the managers to have the heating and cooling appliance assessed by an a/c rep so that it maintained optimal levels. Cooling professionals from the dwelling comfort dealer came to the lab the following afternoon and were stunned by the condition of the commercial air conditioning appliance. The quality cooling system filter was entirely filthy with all sorts of pollutants including unquestionably dangerous chemical residue that all the people at the plant were totally inhaling in. No wonder there had been a bunch of cases where employees had contracted numerous types of respiratory diseases… Other components of the appliance were worn out from years of neglect. The specialists recommended replacing the appliance with a quality Heating and Air Conditioning system, a hybrid Heating and Air Conditioning appliance. They would embed a smart Heating and Air Conditioning to improve its efficiency. All the needed components such as the programmable thermostat were provided by the local cooling and heating business. The management of the chemical plant was especially grateful to my father for illustrating the importance of having an air conditioner worker assess a device often.