The TTC has been disinfecting its transit stations and vehicles for more than a month.
Officials confrm the order was given by the Transit Commission's CEO as a precaution against the spread of the COVID-19 virus.
Cleaning crews started to perform the extra procedures at the end of January.
So-called 'touch points' are treated with a hospital-grade disinfectant liquid as vehicles and stations end their service for the day.
Areas like hand rails, ticket machines, straps, and buttons are wiped down in order to prevent germs.
TTC officials claim the effort was taken on only as a precaution and was not carried out by order of public health authorities.
A TTC spokesperson says it is the largest program of its kind ever launched by the Transit Commission.
Recently, the provincial public transit agency announced it has implemented increased cleaning measures on GO trains.