In the old times they just laid a huge sheet of acetate on the table and poured the emulsion on it. Making multiple layer films this way is impossible but a single layer is not too bad. Super xx was the last single layer film, which is what many of us LF people want anyway.
I dont see any pollutant 'side streams' from this process either.
EK probably made most of their raw materials and this would explain the pollutants. Somebody doing this in their garage would be buying all their starting materials.
The dyes used to sensitize the emulsion are well known.