What is the ruling on workers praying in the factory outside its prescribed time, and is it permissible for them to combine prayers in this situation?

Delaying prayer beyond its prescribed time is a major sin, and being preoccupied with work is not an excuse for it, because the reasons for combining prayers are specific (travel, fear, rain, illness). A Muslim must prioritize prayer over work and trade, for Allah provides sustenance to those who fear Him.