Which class/division of explosions is known to generally cause severe structural damage to adjacent objects?

The correct choice is the classification of 1.1 in the context of explosives. This class refers to substances and articles that have a mass explosion hazard, meaning that when detonated, they can produce a shock wave powerful enough to cause significant structural damage not only to the explosion site but also to nearby structures and objects.

Class 1.1 explosives include materials like dynamite and large quantities of other high-energy explosives. Their capacity for a mass explosion makes them particularly hazardous, as the resulting blast can have extensive destructive effects over a wide area, impacting structures and safety far beyond the immediate vicinity of the explosion.

In contrast, other classes such as 1.2, 1.3, and 1.4 describe explosives that have a reduced risk of mass explosion or present less serious hazards to surrounding structures, thus highlighting why 1.1 is particularly noted for causing severe structural damage. Class 1.2 refers to explosives that could project fragments but do not have a mass explosion hazard, while 1.3 encompasses explosives that have a fire hazard and can produce a localized explosion without significant blast effects. Class 1.4 captures low-risk explosives that pose minimal risk of explosion and thus have even less potential for causing structural damage.