More and more cargo is being classified as haz-mat that didn't used to be. Sacks of dry chemical, fertilizers, paint pigments, garden supplies, stuff like that.
The haz-mat endorsement is a PITA to get but it's worth it. It makes the driver more valuable to the company because it increases the range of cargo he can carry.
Our company hauls very little flatbed hazmat but we still require the driver to have it. We pay for it, too.