One requirement of loading Class 8 materials would be `_________`.

A Load breakable containers of corrosive liquid one-by-one if loading by hand.

explanation

Class 8 (corrosive) materials:
If loading by hand, load breakable containers of corrosive liquid one by one. Keep them right-side up. Do not drop or roll the containers. Load them onto an even floor surface. Stack carboys only if the lower tiers can bear the weight of the upper tiers safely.