Many welders use compressed gases when they do their welding, cutting, and other processes such as descaling, heating, and straightening. The reason is that the equipment is fairly inexpensive, is versatile, and is easy to move around where you need it to be. Gas welding is used in many places, including machine shops, garages, in plant maintenance, engineering workshops, and in construction.
This in itself is not a problem. The problem occurs when people are so used to seeing and using gas welding equipment that they forget about the dangers that come with it. There are lots of people who are injured every single year by being careless or using the oxy/fuel gas equipment. There are some deaths.

Hot work needs a permit to work that will detail what is going to be carried out, how, and when. It also will tell you the precautions that you need to take. If the permit system is written, it is more likely that more care and supervision will be provided. Never use gas welding equipment unless an experienced supervisor or manager has authorized it.