Contract workers having no identity cards in pharma company

Dear Knowledgeable Members,

I work in a reputed Mutinational Pharmaceutical Ltd Company . During my line of work, I have notice many Contract workers like electricians, Painters, etc having no ID Cards but they are working by just making entry in a note book regarding their working hours.

My question is

1) Is this permissible under present indian laws??

2) If any accident or incident happens to such type of persons, who is responsible for their well being..?? Is it the Company or the Contract workers themselves??

3) Is there any other method to solve this problem under present law..??

Thanks