Can an employer refuse to disclose information to the union for the purposes of collective bargaining?

Failure to provide information for the purposes of collective bargaining may result in the union applying to the Central Arbitration Committee. However, an employer may refuse to disclose information if it has been supplied to the employer in confidence, if it relates to a particular individual or if its disclosure would "cause substantial injury" to its business for reasons other than its effect on the collective bargaining.