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NTHU Takes the Lead in the Safe Disposal of Old Gas Cylinders
In many university laboratories we can find numerous old gas cylinders, often corroded and lacking clear labeling, and sometimes these hidden time bombs explode. With guidance and subsidies provided by the Environmental Protection Agency (EPA) and the Ministry of Education (MOE), beginning last year NTHU has safely disposed 61 such cylinders by puncturing them and neutralizing the toxic gases inside. During the process NTHU has also established a standard operating procedure for the safe disposal of old gas cylinders, and this is being made available to other universities and laboratories in Taiwan.
 
Ten years ago when one of NTHU’s labs was being dismantled, and in the depths of one of the storerooms about a dozen unidentified gas cylinders were discovered, some of which were covered with rust and had valves that couldn’t be opened. Further investigation revealed that many of the laboratories on campus had such “orphaned” cylinders, some of which were placed in busy corridors, constituting an accident waiting to happen.
 
Hwang Kuo-chu, the deputy director of NTHU’s Environmental Protection and Occupational Safety Center (EPOSC), said that the gas remaining in old cylinders can be roughly classified into three categories: combustible, corrosive, and toxic. For example, a leaking fluorine gas cylinder tends to produce highly corrosive hydrofluoric acid. Even more dangerous are the colorless and odorless phosphine and arsine—the key ingredients of nerve gas, a single whiff of which can be fatal. Moreover, the high pressure inside a cylinder means that it can easily explode if not handled properly. In principle, each gas cylinder should be clearly labeled, and when it’s empty or no longer needed it should be returned to the supplier for processing. However, it sometimes happens that the supplier is unknown or has gone out of business; in light of such inevitabilities, there should be a centralized processing facility, but currently such a facility doesn’t exist in Taiwan. To deal with this hidden danger, NTHU turned to the EPA and MOE for assistance. To assist this project, the EPA has provided a variety of imported equipment, including a device for safely puncturing cylinders with frozen valves and transferring the contents into a new container, as well as a chemical analysis device for determining the contents.
 
After the old cylinder is sealed within the airtight vessel, an inert gas is introduced into the chamber; then the cylinder is punctured with a spike fitted with a special gasket which prevents the production of sparks. Once the contents of the old cylinder is transferred into a new container and positively identified, the procedure for safely neutralizing it is determined: combustion, washing with water, adsorption, or chemical reaction. The whole procedure resembles that used for disabling unexploded bombs.
 
EPOSC engineer Tu Chia-lin said that even when using proper procedures and specialized equipment, there is always a certain sense of apprehension when puncturing a cylinder holding an unknown substance. Thus they began the operation by dealing with relatively low-risk cylinders, gradually honing their skills before finally dealing with the 21 cylinders containing highly toxic gas. During the process they actually discovered that some of the cylinders were mislabeled.
 
The project was made possible by funding and technical guidance provided by the EPA and MOE; NTHU itself spent NT$3.5 million on the clean-up project. Vice President of General Service Yan Dung-yung said that the project could not have been brought to a successful completion if not for the diligent efforts of his last three predecessors, especially Lee Min and Lyu Ping-chiang, who solved a variety of difficult legal and technical problems.
 
The handling of cylinders with unknown contents was personally supervised by Minister of EPA Chang Tzi-chin, Toxic and Chemical Substances Bureau general director Hsieh Yein-rui, and MOE’s senior specialist Chiu Jen-chieh. Chang said that the most difficult part of the operation was convincing faculty members to hand over the old cylinders, adding that Tsinghua has done a particularly good job in this respect, and that its approach can also be used by other universities.
 
According to Hsieh, many universities in Taiwan have stockpiles of unidentified chemicals, many of which are toxic or explosive, which need to be properly disposed of—sooner rather than later.
 
Senior vice president Lyu Ping-chiang said that some of these unidentified gas cylinders are over 30 years old, and could explode at any time. He also thanked the EPA for making such a concerted effort in dealing with this hidden menace.
 

The disposal project’s supervisory team (left to right): Chiu Jen-chieh, Chang Tzi-chin, Lyu Ping-chiang, and Hsieh Yein-rui.

The disposal project’s supervisory team (left to right): Chiu Jen-chieh, Chang Tzi-chin, Lyu Ping-chiang, and Hsieh Yein-rui.


Senior vice president Lyu Ping-chiang (left) personally thanking Chang Tzi-chin for the EPA’s assistance in the disposal project.

Senior vice president Lyu Ping-chiang (left) personally thanking Chang Tzi-chin for the EPA’s assistance in the disposal project.


A total of 61 old cylinders have already been safely processed.

A total of 61 old cylinders have already been safely processed.


An old cylinder being inserted into an airtight rupture vessel for safe processing.

An old cylinder being inserted into an airtight rupture vessel for safe processing.


After removing the contents, some cylinders have to be soaked in water to neutralize any residual toxins.

After removing the contents, some cylinders have to be soaked in water to neutralize any residual toxins.

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