At around 8:15 a.m., residents in the city of Charleston (West Virginia, USA) alerted the local environmental agency after noticing a sweet mint/liquorice type chemical smell in the air that was stronger than usual. At about 11 a.m., inspectors traced the odour to the site of a wholesale chemical products distribution company and questioned the director. He stated that he was unaware of the origin of the nuisance until an employee took him aside to inform him of a leak on a storage tank containing 110 m³ of a mixture of 88% 4-methylcyclohexanemethanol (MCHM) and 8% glycol ether (chemicals used to wash coal and remove impurities before it is used in a coke oven). On site, the inspectors discovered a transparent liquid flowing from several holes at the bottom of the tank, spilling onto the floor of the containment area, trickling into the joint between the wall and the floor of the containment before flowing down to the river. Employees urgently poured a bag of absorbent product while the inspectors finished convincing the director to officially report the leak.

Twenty-eight cubic metres of product was released into the ELK river. The pollution was detected late as the surface of the water was frozen. The authorities alerted the drinking water treatment station, located 1.6 km downstream, but its operator assumed that its active carbon filters could stop the pollutants. By 4 p.m., the filters were saturated, and the chemical products were again detected in the distributed water supply. The operator researched the toxicological information about the pollutants before declaring the water unsafe for use at 5:45 p.m.

The authorities required the operator to empty the 17 storage tanks owing to the weak containment areas. The site was placed under court-ordered sequestration after 4 days.

Following the spill, up to 300,000 residents within nine counties were without access to running water for 4 to 10 days, and the authorities organised distributions of bottled water. School systems, hotels and restaurants in the region were closed, and the damage was estimated at $61 million. The delay in informing the users resulted in 1862 telephone calls asking about intoxication symptoms; 411 of these calls resulted in medical consultations for nausea and skin irritations, and 20 people were hospitalised. The social networks criticised the authorities’ management of the information (delay, actual toxicity of the product, choice of the contamination threshold to consider the water potable, etc.).

Sixty-two lawsuits were brought against the operator, which went bankrupt. Several months after the accident, the site was still awaiting demolition and traces of methylcyclohexanemethanol (> 1 ppm) were still detected in the tap water of some houses in the area affected.

The storage tank was not subject to any federal or local administrative control because the mixture was not classified as hazardous, and the site did not conduct any manufacturing activities.

The brick and concrete containment area had numerous holes and cracks, such as the other containment areas at the site for which the company made financial provisions for scheduled repairs. The tank was over fifty years old and had previously been used to store fuel and pumping water from coal mines. The operator did not have a back-up plan in the event of a chemical leak, even though it this was required by the regulations. Press coverage echoed pressure from the local environmental agency to moderate regulatory control and sanctions at sites associated with the coal mining and processing industry, dominant in the state of West Virginia. The operator’s hypothesis is that the bursting of a water pipe under the containment area’s foundation during the extreme cold period would have caused a sharp object to pierce the lining.