However , since the contractor has produced a letter from the tung chung rural committee ( tcrc ) , claiming that the materials came from the flood protection project for the stream now underway , the consultant considers that before establishing the " non - legality " of the source , there are difficulties in invoking the terms and conditions of the contract to stop the contractor from transporting such materials to the construction site at its own risk and bearing all consequences and liabilities 但由于承建商曾出示一份东涌乡事委员会发出的信件，声称石料乃来自进行中的东涌河治河工程，工程顾问表示在未能确定该等石源是非法前，若根据工程合约条款禁止有关承建商在自负所有可能后果及责任的情?下运载石料进入工地，实存在困难。
