What should not be allowed to accumulate on machinery?

Oil, grease, and combustible material should not be allowed to accumulate on machinery due to the significant risks they pose. These substances can create hazardous conditions that may lead to fires or explosions, especially in environments where heat or sparks are present. Furthermore, the presence of such materials can interfere with the proper functioning of machinery, leading to mechanical failures or reduced efficiency. Regular cleaning and maintenance are essential to prevent these accumulations and ensure the safe operation of equipment, which is a fundamental responsibility for a surface foreman in maintaining a safe work environment.

While the other options can also lead to less efficient operations or become a nuisance, they do not carry the immediate and serious risk that oil, grease, and combustible materials do, making their management a critical focus in operational safety protocols.