Tokyo official raises sarin gas claim

A Japanese official on Tuesday baselessly claimed that certain industrial materials shipped to South Korea may be used to produce toxic sarin gas to justify Tokyo’s recent restrictions on exports to Korea.

In a report by Japanese public broadcaster NHK, an unnamed government official in Tokyo claimed last week’s export restrictions to Korea were made on the basis of several “inappropriate, security-related” risks, particularly regarding hydrogen fluoride, which he said may be used to make the nerve agent sarin.

The official said that Japan’s Ministry of Economy, Trade and Industry warned Japanese firms exporting hydrogen fluoride, also known as “etching gas” due to its use in etching semiconductor wafers, to Korea about the issue. The official said that Korean authorities did not take precautionary measures due to their “insufficient oversight over trade practices.”

He continued that there was concern that such material with military capacities could be transferred from South Korea to “other countries producing weapons of mass destruction,” an apparent reference to North Korea.

Last week, Japan announced tighter restrictions on exports to South Korea of three key materials used in semiconductors and displays, including fluoride polymide, photoresists and hydrogen fluoride, escalating a diplomatic row between the two countries over court-ordered compensation for Japanese companies’ use of Korean forced laborers during World War II.

Tuesday’s NHK report follows a public suggestion by Japanese Prime Minister Shinzo Abe on Fuji TV Sunday that key industrial materials could have made their way to North Korea and been used to produce chemical weapons. South Korea’s Minister of Trade, Industry and Energy Sung Yun-mo rebutted these earlier claims on Tuesday, saying that there was no evidence that etching gas was leaked to United Nations-sanctioned countries like North Korea.

A Blue House official on Monday also told reporters that the burden of proof for such baseless claims was on Japan’s side, and that Seoul continues to strictly abide by international sanctions on North Korea, which ban the transfer of any material that can be used for its nuclear program. Chemical experts and businesses in South Korea also cast doubt on Tokyo’s claims.

While hydrogen fluoride is indeed used to produce chemical weapons as well as enrich uranium, the type used for these purposes is usually low purity varieties of the chemical that have a purity rate of less than 97 percent and are easily obtainable in many places, such as China.

By contrast, the type of hydrogen fluoride imported for semiconductor etching purposes has a purity rate of more than 99.999 percent.

Japanese companies account for over 90 percent of the world’s production of such high-purity variants of the chemical. “In the past, when [North Korea] made toxic gas or enriched uranium, [they used] low purity hydrogen fluoride,” said Lee Duck-hwan, a chemistry professor at Sogang University in Seoul. “There is no reason why [they] would use highly enriched Japanese hydrogen fluoride, which is expensive and hard to acquire.”

A source from South Korea’s Trade Ministry also questioned the logic behind Japan’s claims, saying that it implied Seoul was taking the hard route of sending Japanese-made high-value material to the North when alternatives were so readily available.

Other sources said it is practically impossible for such material to be leaked abroad, given the high scrutiny placed on its maintenance by firms.

“Among various imported raw resources, toxic materials like hydrogen fluoride are closely monitored so that the amount ordered is identical to the amount warehoused,” said a source from a Korean semiconductor firm. “It is impossible for hydrogen fluoride to flow outside the country.”

Analysts in Korea say Tokyo’s groundless claim about sarin gas is intended to convey a political message to the Japanese public.

Sarin gas has a particularly notorious reputation in Japanese public memory, as it was the agent used by a domestic doomsday cult called Aum Shinrikyo in a terrorist attack on Tokyo’s subway system in 1995 that left 12 dead and thousands sick.

In July last year, Japan carried out the execution of Shoko Asahara, the cult leader responsible for the attack, bringing the incident back into the public’s eye.

By singling out the possibility of sarin gas being produced by the materials Tokyo restricted, the Abe administration may be trying to drum up public support for its economic retaliation against Korea ahead of Japan’s upper house elections on July 21.

BY SHIM KYU-SEOK, KIM KI-HWAN [shim.kyuseok@joongang.co.kr]