Some officials of the Ceylon Petroleum Corporation (CPC), allegedly involved in the oil hedging deals, are attempting to conceal evidence with regard to the issue, senior CPC trade union members charged. The new CPC Chairman Major General Asoka Thoradeniya was not available for comment. When this newspaper tried to contact the CPC chairman over the phone on Thursday, one of his aides, Capt. S. Weerasinghe said that the chairman was busy and could not be reached.