The use of industrial trucks with diesel engines is prohibited inside enclosed spaces because of the associated diesel soot pollution. However, since diesel forklifts are highly valued outdoors, due to their long range and generally high performance, the load would have to be transferred at the entrance to enclosed spaces.
Diesel soot filters provide a remedy. With such filters, the combustion engine can be used short term indoors. Exhaust filters are practical for use in halls, on ships, fairs, etc., if they can be left immediately after unloading.