Since the 1988 pro-democracy uprising, strategic analysts monitoring developments in Burma (Myanmar) have been on quite a roller-coaster ride, particularly with regard to weapons of mass destruction (WMD).

Over the past 25 years, both the former military regime and President Thein Sein's reformist government have been accused of developing a nuclear device, manufacturing ballistic missiles, deploying biological agents and using chemical weapons (CW). These capabilities were reportedly acquired mainly with the help of North Korea and China.

Such is the dearth of reliable information about Burma's armed forces and national security that it has been difficult to prove or disprove many of these claims. However, enough of them have been shown to be exaggerated or false to warrant a fair degree of caution when considering any fresh accusations of WMD production or use.

With that in mind, it is worth looking closely at reports in the news media over the past few weeks that a secret chemical weapons plant has been discovered in Burma.

The Rangoon-based Unity Journal has claimed that in 2009 a CW factory was built on 12 sq km of land confiscated from farmers in Pauk township, near Pakokku in central Burma. Citing local informants, the journal said that the complex (possibly known as DI-24) included over 300m of tunnels, and was receiving technical help from China.

Following publication of this story, four journalists and one Unity executive were charged under the 1923 State Secrets Act, which prohibits trespassing on and photographing defence facilities in Burma, and divulging classified information. All unsold copies of the weekly journal were seized. Naypyidaw also flatly denied the existence of any CW plant.

Local news outlets have highlighted the perceived attack on freedom of the press in Burma, which has been vigorously exploited since Thein Sein relaxed controls on the media in 2012. International observers seem more concerned about the apparent revelation of a CW plant and Burma's failure to ratify the 1997 Chemical Weapons Convention (CWC).

Some background to the latest claims and Burma's current CWC status might help put these issues into perspective.

Since the mid-1980s, several ethnic armed groups have claimed to be the victims of chemical warfare. They have described attacks by the Burmese armed forces with mortars, artillery, rockets and air-delivered bombs that left insurgents and displaced communities with symptoms including dizziness, nausea, rashes and, in some cases, partial paralysis. There does not seem to have been any fatalities.

Such claims continued to be made after Thein Sein's inauguration in March 2011. In June, for example, Shan insurgents reported that they had been bombarded with artillery shells containing noxious chemicals. Also in 2011, Kachin groups said that they had been subjected to 'yellow rain' and 'toxic gas'. Similar claims were made in 2012.

Without independent expert testimony and rigorous scientific analysis, which have so far been lacking, such reports are almost impossible to verify. It has even been difficult to determine what kinds of chemical agents, if any, may have been employed. Some descriptions have been consistent with the use of white phosphorus, tear gas or even toxic defoliants.

That said, claims of CW use have had some support. In 1984, Western newspapers cited what was reportedly a leaked US Special National Security Intelligence Estimate stating that the Ne Win regime had been making efforts to produce mustard gas since 1981. A West German firm was said to be assisting with the construction of a pilot plant in Burma, with additional equipment imported from Italy.

It was later reported that the US had forced this plant to close down, in part by putting pressure on Bonn. No evidence was ever provided to suggest that any chemical agents had been produced, weaponised or tested. However, as late as 1993, Burma was being listed by some US agencies as possibly having an offensive CW capability

More recently, a few US politicians have referred to Burmese CW use, but this has been in the context of unconfirmed press reports. Also, the issue has usually been raised in an attempt to discredit Naypyidaw's reform program and the Obama Administration's engagement policy. Once again, no evidence was provided to support such claims.

For their part, successive Burmese governments have consistently denied having a CW capability, and of using CW against domestic opponents. Officials have pointed out that Burma has been a strong supporter of the CWC, which it signed in 1993. Some have been of the view that, as Burma was then directly ruled by a military council, this automatically included ratification.

Despite all the claims made over the years, some of which have included descriptions of purported CW facilities, the fact remains that no-one really knows if Burma has ever developed a CW capability or has used CW against armed ethnic groups. There is simply not enough reliable information available from public sources either to dismiss these claims or confirm them.

As regards the latest reports, it is possible that the site investigated by the Unity journalists was another kind of defence industrial plant, as claimed by a government spokesman. Many such facilities have been built since 1988, often for unknown purposes. A number have 'tunnels'. And Burmese authorities have always been very sensitive to breaches of security.

It has been argued that Thein Sein's reforms make chemical weapons 'near redundant'. Burma’s circumstances have certainly changed, but CW has enduring strategic applications. If Naypyidaw is developing ballistic missiles, as many suspect, then possession of a chemical warhead would constitute a strong deterrent and a powerful bargaining chip in international negotiations.

It is in this context that Burma's ratification of the CWC has become more pressing. Last year, the Organisation for the Prohibition of Chemical Weapons conducted a 'national awareness workshop' in Naypyidaw. The Burmese government later announced that it would ratify the convention, a decision that has just been reconfirmed

This step would doubtless be presented as evidence of Burma's readiness to be a good international citizen and, as such, would be applauded by many. However, it is unlikely to have any appreciable impact on domestic political developments. Indeed, as long as Naypyidaw continues to deny any past CW attacks, ratification will be seen by most ethnic groups as little more than a public relations exercise.

Another reason why ratification of the CWC is unlikely to attract unqualified approval is that, despite repeated protestations to the contrary, Burma maintains military ties with North Korea. Thein Sein's government could accede to all the international instruments relating to WMD but, as long as that issue remains unresolved, suspicions about Naypyidaw's bona fides are bound to remain.