Until when is CHI's QEHS MS certification valid?

CHI's QEHS MS certification is valid for three years from the date of issuance.  Surveillance audits are to be done by the certifying body at least once a year, aside from the internal QEHS audits done by our internal auditors.  In our case, we had opted for twice a year surveillance audits. Our last re-certfication audit was conducted from Febuary 21 to 22, 2012.