The Through Bill of lading is virtually identical to the Multimodal Transport Bill of lading but with one major difference:
The Multimodal Transport Bill of Lading is issued by the Multimodal Transport Operator (MTO) (generally the sea carrier) and he takes responsibility of the goods (e.g. shortages, losses, damages) during the entire period of transport, thus not only for the sea passage but also for the other transport modes. (See also the Multidoc 95 Clauses, Part III, Liability of the MTO.)
The Through Bill of Lading is issued by the sea carrier but he states on it that he is only responsible for the goods for that part of the carriage he takes care of, thus the sea passage.
Under the Through Bill of lading, if the goods do not reach their final destination, as stated in the B/L, it is customary to involve the last carrier who has a recourse on the previous carrier.
It is obvious that the carrier, who is not at fault, and who made the necessary reserves (remarks) when he received the goods for further transportation, shall refuse any responsibility regarding shortages, losses or damages to the goods as per his remarks made. The carrier who was found at fault will then be liable without having to start a chain reaction from one carrier to another. It is thus very important that the carrier or his representative (master or agent) ascertains himself that the goods he receives really correspond with their description in the bill of lading. If this is not the case, it is imperative to specify this in writing before taking over the goods.
In case it was impossible to determine where the goods were damaged or lost, it will be assumed that it happened during the sea voyage:
"(III) If it cannot be proved where the goods were when the loss or damage occurred, the loss or damage shall be deemed to have occurred at sea and the Carrier shall be liable to the extend prescribed by the Hague Rules". (Conventional Through Bill of Lading, Clause 2, Responsibility for Conveyance, discharge and delivery.)
The content of this clause shows clearly that the sea carrier is considered as the main carrier.
VERY IMPORTANT REMARK
The United Nations Convention on International Multimodal Transport of Goods has not yet entered into force so that departures from the Rules are possible. In practice, both types of bills of lading may still be used and it is imperative to read the clauses carefully especially those related to the responsibility of the person issuing the B/L.