The plant had implemented 100-year anti-flooding measures. However, the flood exceeded the 100-year flood by 1.3 m, and the severity of the flood was not forecast by authorities and was hence not expected by the plant.

Off-site sheltering

In addition, police and military were involved in the emergency response.

In the wake of the release a class III chemical alert was declared as a precaution although the chlorine concentrations within the plant borders were below the class III alert threshold.

Measured aimed at containing the spreading of chlorine, and the safe transfer of the chlorine remaining in the damaged tanks to alternative storage once the floodwaters had receded. Also, the public was alerted by the media to shelter in place for protection.

Staff and emergency responders were at risk from the chlorine release.

In addition to the chlorine release, significant quantities of hazardous substances (e.g. dioxins, etc.) were released from the plant into the Elbe river, however, it was sustained that no risk to human health existed.

Severe damage to flora in the surroundings of the site was observed (chemical burns).

Analyses in the aftermath of the event showed that dangerous quantities of dioxins that leaked from the plant settled in sediments on the shores of the Elbe River. It was found that dioxin levels in the village of Libis, half a kilometre downstream from the flood-damaged facility, were three times higher than safety norms.

The most critical flooding of old ecological loads was detected in a locality of the chemical plant (installation for amalgam electrolysis (mercury) and dioxin installations). The flooding of these installations was reflected in an increase in mercury and dioxin in water and sediments. However, the Czech Environmental Inspectorate sustained that this increase was of a local importance except for contamination of Libis locality.

A newspaper article estimates that the economic losses due to the flood-related damage amount to 750 million Czech Crowns (approximately 29 million Euro).

The public had to shelter in place.

Following the accident, technical and organisational protection measures were implemented to prevent the re-occurrence of such an accident in case of a flood of the same or higher severity.

After the accident, a guide-rail structure for vertical guiding of the tanks was installed. This will avoid unwanted horizontal motion of the tanks in case of displacement. This measure was accompanied by a segmentation of the walkways which will move together with the tanks in case of floating.

Chlorine storage was reduced to 50% of the capacity before the accident and therefore to one storehouse only, thereby significantly reducing the accident risk.

Also, prior to each scheduled shutdown of the sodium hypochlorite plant, chlorine is removed from the manifolds and pipelines, and before each scheduled power outage or disruption of cooling water supplies, the pipeline connecting the tanks in the storehouse must be disassembled.

Based on the experiences of the accident, all entrance doors to the storehouse were replaced with gas-tight doors with fuses against internal pressure overload. If the pressure exceeds the building's design pressure limit, special windows will open, release the pressure, and a balance weight will close them again. Water curtains were also installed to capture the chlorine that escapes in this way.

Before the accident, emergency monitoring detectors had been installed only around the storehouse. Afterwards, detectors with a control light and an uninterrupted power supply were also placed inside the storage at an elevated location to prevent them from being affected by flooding.

The emergency exhaust system was improved to allow suction of the released chlorine from the upper part of the storehouse. This is important if the retention basis are flooded.