Knox transfer station goes up in flames again.

A fire at a recycling facility that caused a large plume of smoke to blanket part of Melbourne's east is under control.

Firefighters were called to the Knox Transfer Station at Wantirna South, just off EastLink, shortly after 4.30pm Saturday, but by 8.30pm authorities said the blaze had been contained.

The CFA said more than 400 mattresses were burning with upwards of 50 firefighters at the scene during the height of the fire.