What is a disadvantage of using steel shores?

The correct focus is on the tendency of steel shores to produce sparks during certain applications. When metal is struck against metal or subjected to high stress, friction can cause small particles of steel to ignite, leading to sparking. This is a significant consideration in fire-sensitive environments or where flammable materials may be present. Utilizing steel shores in such conditions could pose a serious hazard, which is why this disadvantage is crucial to recognize.

In terms of the other characteristics of steel shores, while they might bend under excessive loads, rust is indeed a well-known issue due to the susceptibility of steel to corrosion if not adequately protected. However, the tendency to crack is not typically associated with steel — it's more of a problem observed with materials like concrete or certain types of plastics. The specific risk of producing sparks makes it a noteworthy drawback in particular operational contexts.