Help: Breeze Blocks - Yellow Residue/Powder on Surface

Hi,

The inside wall of my loft is made of breeze blocks -- dark course grained blocks. On the surface of a number of the blocks are nodules (1 to 2cm wide) which have a yellowish powder surrounding them. Some of the powder is leaking/dropping onto the loft floor.

Any ideas what this could be? Is it harmful?

Thanks,

Andy

Not 100% sure but it might be either fungal growth or just a bit of effloresance. Either way stick on a mask and hoover/ brush off. Do not wet as effloresance will just dissolve back into your bricks . Then paint on an anti fungal solution. Both problems are assosiated with damp i'm afraid.

I`ll bet they are made from power station waste...........and the yellow blobs are sulphur