If your unit is covered under the ESI & PF Acts then the contract workers will also be covered under these Acts. If the contractors fails to deposit the contribution of their workers then Principal Employer will also be held responsible for non compliance. Thus ultimate responsibility lies with the P. E. For more details you can aslo open the site of esic.nic.in & epfoindia for these two Acts in question. Bare Acts are also available in market.
(Labour Law & Legal Consultants)
20th April 2009 From India, Delhi