* Tanker carrying 75,000 tonnes of naphtha -official
* Cargo estimated to cost more than $30 mln -trade sources
* Ship scheduled to arrive in Taiwan in July -official (Adds comments)
By Liang-Sa Loh and Yimou Lee
TAIPEI, June 13 (Reuters) - An oil tanker carrying fuel from the Middle East for Taiwan's state oil refiner CPC Corp was suspected to have been attacked earlier on Thursday, the company said.
Oil tanker Front Altair was carrying 75,000 tonnes of naphtha, a petrochemical feedstock, when it was "suspected of being hit by a torpedo" around noon Taiwan time (0400GMT), Wu I-Fang, CEO of CPC's petrochemical division, told Reuters.
He said all crew members have been rescued.
Front Altair was last seen off Iran in the Gulf of Oman after loading its cargo from Ruwais in the United Arab Emirates, according to shipping data on Refinitiv Eikon.
The ship was chartered by shipping company Ocean Energy on behalf of CPC, while the cargo was sold by Abu Dhabi National Oil Company (ADNOC), CPC said in a statement on its website.
CPC said the extent of damage to the ship and the volume of naphtha lost was not immediately clear.
The cargo is worth more than $30 million, according to estimates from trade sources.
Wu and CPC did not provide a value.
The ship was scheduled to arrive in Taiwan in July, Wu said.
CPC has started making plans for its production and sales after the incident, including examining the company's inventory, he said.
The company said the incident will not affect its oil products and petrochemical supplies. (Reporting by Liang-Sa Loh and Yimou Lee in TAIPEI; Additional reporting by Seng Li Peng and Florence Tan in SINGAPORE; Editing by Tom Hogue)