5.__Secured releases.__Under a contract made for a public improvement, the contractor may withdraw retained funds upon depositing with the Treasurer of State or the public owner negotiable public securities or certificates of deposit greater in value than the amount withdrawn.

6.__Authority of Treasurer of State or owner.__The Treasurer of State or public owner shall pay over to the contractor all net income from the escrowed securities as it is received.__ The Treasurer of State or owner may contract with a suitable financial institution for custodial care and servicing of any securities deposited pursuant to this section.

7.__Deductions.__Any amount deducted by the public owner pursuant to the terms of the contract from the retained payments due the contractor must be deducted first from that portion of the retained payments for which no security has been substituted, then from the proceeds of any deposited security.__In the case of a deduction from the proceeds of a deposited security, the contractor is entitled to receive interest, coupons or income only from those securities that remain after such amount has been deducted.

8.__Assignments.__Any assignments of retained payments made by the contractor must be honored by the party holding the securities as part of the procedure to accomplish the substitution of securities under this section, as long as the assignment is not made without prior notification to the contracting agency of the State and the party holding the securities.__Such assignment may not impair the equitable rights of the contractor's surety in the retained payments or in the securities substituted for the retained payments in the event of the contractor's default in the performance of the contract or in the payment of labor and material bills or other obligations covered by the surety's bond.

9.__Environmental control costs.__Any contract made for a public improvement must include the cost of environmental control measures required for execution of the contract; the cost of environmental control activity that is required by legislation or rules passed or adopted after the date on which bids are received for the project for which such contract is made or awarded must be paid for in an equitable manner.