US  Secretary of State Rex Tillerson made clear at a press conference on March 17 in Seoul, South Korea that Washington’s “strategic patience” with North Korea has ended after a series of provocative actions and that some sort of military intervention against Pyongyang could be on the cards.

Last month’s murder by nerve agent of North Korean leader Kim Jong-un’s half-brother Kim Jong-nam at the Kuala Lumpur airport in Malaysia, however, casts doubt on the ultimate strategic utility of potential US air strikes against the secretive country’s many military installations.

It would not be difficult for US fighters to hit the bases on North Korea’s northeastern coast, from where missiles have been launched in recent provocative test fires, or even to demolish some of its known nuclear facilities at Yongbyon north of the capital Pyongyang or the Punggye-Ri testing site situated in the country’s northeast.

Last month’s murder by nerve agent of North Korean leader Kim Jong-un’s half-brother Kim Jong-nam at the Kuala Lumpur airport in Malaysia, however, casts doubt on the ultimate strategic utility of potential US air strikes against the secretive country’s many military installations.

It would not be difficult for US fighters to hit the bases on North Korea’s northeastern coast, from where missiles have been launched in recent provocative test fires, or even to demolish some of its known nuclear facilities at Yongbyon north of the capital Pyongyang or the Punggye-Ri testing site situated in the country’s northeast.

But unlike nuclear reactors and missile launching grounds which can be easily detected by satellites, North Korea’s chemical and biological weapons facilities are known to be hidden underground. And Pyongyang’s use of the lethal VX nerve agent in a transnational assassination has sent a chilling warning of its apparent willingness to use biological and chemical weapons in a conflict scenario.

How the nerve agent was transported to Malaysia is still unclear. Some analysts suspect it could have been moved through a diplomatic pouch which is not checked through during normal customs procedures. The alleged involvement of Kuala Lumpur-based North Korean diplomats in the apparent plot has lent credence to the speculation.

What is known is that North Korea has for years produced chemical and biological weapons at factories in Kanggye in Chagang province near the Chinese border in the country’s north and at Sakchu in North Pyongan province. Both facilities are known to operate underground.

Some chemical weapons have in the past been field tested on islands in the Yellow Sea, off the coast of northwestern North Korea. Causeways link some of those islands with the mainland but no buildings can be seen on them from the air as the facilities are hidden under the earth’s surface.

North Korea’s chemical and biological weapons research began in 1954 when Pyongyang, then in the throes of the Korean War, established a directorate known as the “Central Bureau” to develop defenses against chemical weapons as well as to provide doctrinal provisions for the deployment of chemical warfare-trained troops.

Each airfield in North Korea was provided with decontamination equipment and detection systems derived from Soviet and Chinese designs and partly supplied by those two countries. In 1961, then leader Kim Il-sung — Kim Jong-un’s grandfather — issued a “Declaration of Chemicalization”, which called for greater efforts to develop facilities where chemical weapons would be produced.

That declaration is apparently still in effect. Dual-use chemicals such as phosphate, ammonium, fluoride, chloride and sulfur have recently been procured by Pyongyang from abroad. Those chemicals can be obtained easily anywhere in the world and have legitimate civilian uses but those procured by North Korea are known by analysts to have been used to feed the country’s chemical weapons factories.

North Korea is also believed to have significant stockpiles of different kinds of chemical and biological warfare agents, all produced in its underground installations and then stored at Maram-dong near Pyongyang and at Anbyon in the southern border province of Kangwon. Both facilities consist of mazes of tunnels dug into mountains and cannot be detected from the air.

Less is known about the origin of raw materials used in North Korea’s biological weapons factories. The US Defense Intelligence Agency (DIA) said in an unclassified report in 2007 that “North Korea’s resources include a biotechnical infrastructure that could support the production of various biological warfare agents. DIA believes North Korea has a longstanding chemical weapons stockpile of nerve, blister, blood, and choking agents.”

The nerve agent VX, or “venomous agent X”, is a tasteless and odorless liquid that was first developed in Britain in the 1950s. The US began producing it in 1961 at Newport Chemical Depot in the state of Indiana. The UN classifies VX as a weapon of mass destruction.

It has been banned by international conventions and cannot be used for anything except in chemical warfare. The US cancelled its chemical weapons program in 1969 and began destroying its stockpiles, first on Johnston Atoll in the South Pacific and later on the US mainland. The last of its chemical weapon stockpile was destroyed in December 2008.

It is uncertain when North Korea began its production of VX, but it was most likely in the 1960s when it also began to manufacture other nerve agents such as sarin, soman and tabun. VX, however, is believed to be the deadliest nerve agent ever created, of which even a drop of the lethal substance can kill a human.

After the Kuala Lumpur attack, Raymond Zilinskas, a chemical and biological nonproliferation expert at the Middlebury Institute of International Studies at Monterey, California, said that VX fumes would have killed the attackers even if they were wearing gloves.

He suggested the VX agent used to kill Kim Jong-nam was made up of two non-lethal components that when mixed formed VX on the victim’s face. CCTV footage from Kuala Lumpur airport shows two young women touching Kim Jong-nam, apparently on the face, though the images are too hazy to show exactly what they were doing.

The nerve agent VX, or “venomous agent X”, is a tasteless and odorless liquid that was first developed in Britain in the 1950s. The US began producing it in 1961 at Newport Chemical Depot in the state of Indiana. The UN classifies VX as a weapon of mass destruction.

It has been banned by international conventions and cannot be used for anything except in chemical warfare. The US cancelled its chemical weapons program in 1969 and began destroying its stockpiles, first on Johnston Atoll in the South Pacific and later on the US mainland. The last of its chemical weapon stockpile was destroyed in December 2008.

It is uncertain when North Korea began its production of VX, but it was most likely in the 1960s when it also began to manufacture other nerve agents such as sarin, soman and tabun. VX, however, is believed to be the deadliest nerve agent ever created, of which even a drop of the lethal substance can kill a human.

After the Kuala Lumpur attack, Raymond Zilinskas, a chemical and biological nonproliferation expert at the Middlebury Institute of International Studies at Monterey, California, said that VX fumes would have killed the attackers even if they were wearing gloves.

He suggested the VX agent used to kill Kim Jong-nam was made up of two non-lethal components that when mixed formed VX on the victim’s face. CCTV footage from Kuala Lumpur airport shows two young women touching Kim Jong-nam, apparently on the face, though the images are too hazy to show exactly what they were doing.

This first appeared in AsiaTimes here.