White Powder: IT Cleaning Ltd are cleaning a new data centre. “We found the floor was very slippery, on investigation we discovered the floor was covered in a white powder, this turned out to be Magnesium Oxide and Chalk. These powders are used inside power cables MgO in high voltage and Chalk in 300 to 500v cables.” Stephen Yates. ” Obviously this dust needs to be removed prior to equipment being installed.” Steve.