1. Sir, when a company or unit is manufacturing and employing persons as required under ESI Act, 1948, it becomes a "factory" and therefore, coverable under section 1(4) of said Act w.e.f. the date it employed 10 or more persons provided the area is implemented/notified under section 1(3) of said Act. Even if after coverage, the said factory stops manufacturing process, still the same continue to be covered as laid down under section 1(6) of said Act. The term " manufacturing process" is of very wide connotations and almost also include every repair, maintenance, preservations etc. etc.
2. If the unit is not using manufacturing process since its start and falls under other category of establishments, then the same can still be coverable under said Act, provided that the nature of said unit and minimum persons so required falls within the ambit of notification issued by the appropriate government under section 1(5) of the said Act. In this case also the area must be implemented area within section 1(3) of said Act.
3. As mentioned by Sh.Saji above, I think, this forum could have discussed in more detail had the person who started this thread would have mentioned complete facts and nature of working of said company.