The worker was dug out and sent to a local hospital and is "expected" to make a full recovery.
The general idea is that if a worker is trapped only up to their waist line, it is no big deal. WRONG! It is very common that the pressure to the lower body is such that blood can not circulate to the legs and feet, and victims experience heart attacks. This was not a very deep which gives many companies get lax on cave-in protection. Shallow trench wall collapses can easily cause severe injuries or a fatility.
More "Donkey" methods continue to be used in trenching work when it is so easy to use "Horse Sense" to provide adequate cave-in protection for workers in trenches.
When are trenching companies going to learn that cutting corners and being "Donkeys" DOES NOT PAY? It does not save money nor time, but costs in the lives of their workers, their Insurance premiums and puts them at risk of being put out of business.
OSHA officials and the company are investigating this incident.