Containment failure of hazardous liquid chemicals

A couple of months ago, West Virginia (US) was in a state of emergency due to the leak of 4-methylcyclohexane methanol into river Elk, just about a mile upstream from a water treatment plant intake. It has been understood that domestic water supplies were contaminated by an unknown amount of the chemical.

4-methylcyclohexane methanol is used (as the major compound) in Froth-floatation processes for cleaning coal (to remove impurities from freshly mined coal).

We take this time to remind you of a few key safety aspects related to the containment of dangerous, toxic, or generally hazardous liquid chemicals in bulk quantities.

1. Assess the inherent risks of hazardous chemical storage tanks.
2. Assess the risks posed by the stored maximum quantities.
3. Get to know the maximum allowable storage quantities and other regulations stipulated by the relevant authorities.
4. Ensure that all employees, especially those who are working closely with the process system and the tanks, are aware of the danger posed by the spill of the chemical by containment failure.
5. Make sure that the storage tanks delivered by the suppliers are made according to the necessary engineering standards.
6. Take all necessary safety precautions (including engineering control, and safety functions) to avoid overfilling of tanks.
7. Perform regular visual inspection of tanks for small leaks, corrosion, cracks, bends, other anomalies on the surface, or other structural damages, blocked vents, etc.
8. If visual inspections are leading to suspicious conditions, take the tank out of the process stream immediately and empty the content. Call for a qualified inspection agency to carry out a full and detailed inspection of the tank.
9. Perform detailed tank inspections at predetermined regular intervals.
10. Strongly follow up actions on any recognized weaknesses or problems during such inspections.
11. CONSTRUCT A SECONDARY CONTAINMENT. During the latest West Virginia incident, it is being told that the capacity of the secondary containment has been exceeded by the leak and then the chemical has flowed out of the secondary containment too. THE SIZE OF THE SECONDARY CONTAINMENT MUST BE DECIDED BY A RISK ASESSEMENT JUDGING THE MAXIMUM EXPECTED LEAK RATE.
12. Prepare an emergency response plan for the worst case scenario, i.e. usually the rupture of the whole tank (or a combination of several tanks, if it is likely). Update the emergency response plan on a regular basis.