On 9 September 2013, there was a release of crude benzene on a tank farm when a road tanker was drained. At around 7.42 p.m., the driver of the road tanker connected the facility-side hose with dry coupling to the tanker using an adapter. The flow path up to the last valve on the tanker was then cleared by opening the valves; the valves of the sampling equipment were opened. 

When the tanker driver realised that the hand lever of the valve on the tanker could not be operated by means of the adapter and dry coupling, he disconnected the coupling without closing the valves on the facility side. This caused residual substances still in the hose from the previous draining to be released due to the tank pressure applied via the sampling equipment.

The residual substances released struck the tanker driver’s face and upper body, even though he was wearing the appropriate protective clothing and helmet with protective visor. The tanker driver collapsed. An emergency call was made immediately and first aid was started. After being given first aid by the emergency services, the tanker driver was taken to hospital, where he died after about one hour.

The above is a description of the facts currently known.

Closure of the shut-off valves in the pump flow path.
Removal of the released product.
Closure of the site area until investigations had been provisionally concluded.

Medical examination of the person who witnessed the accident and the paramedics as a precaution.

Failure to close the valves on the facility side of the connection line to the pump.

The valves on the facility-side flow path to the pump were not closed.

Technical measures:

1) In order to prevent product from being released from the coupling when work instructions are not followed due to human error, the adapter used has been modified.
Non-return valve on the adaptor:
The adapter for use on tankers without a dry coupling counterpart is fitted with a non-return valve to prevent any residual products in the hose from being released if the union nut comes loose without having disconnected the dry coupling.

2) Pneumatically operated valves around the sampling equipment:
The pipe connection to the sampling equipment, which is connected in parallel with the product path, has been fitted with pneumatically operated valves, which only open when the drain pump is running.

Organisational measures:

1) Instructions to tanker drivers:
The instruction forms used for the initial and annual training of tanker drivers have been updated and are now available in eight languages. Drivers are given a copy to keep.
New tanker drivers are trained by operator staff in how to operate the installation and are allowed to operate it independently only once they have completed this training.

2) Work instructions:
The work instructions for tanker drivers have been amended in line with the modified installation and allow tankers to be drained:
– with the necessary PPE but without using a respirator mask when the dry coupling is used directly, i.e. without the adapter;
– only with the necessary PPE and using a respirator mask as an additional safeguard against swallowing and inhalation of product residues when an adapter is used. 

The work instructions are posted in the facility in three languages. The following additions have been made:
– Images showing how to correctly connect to the facility;
– Operating instructions concerning the hazardous substances to be drained;
– Operating instructions concerning PPE to be used, including breathing protection. 

3) Risk assessment of the tanker draining facility following the modification:
After testing and introduction of the above-mentioned modification, a new risk assessment was carried out on the tanker draining facility by the external works safety expert. The technical and organisational measures that had been implemented at the time of the assessment were found to be ‘completed and effective’.

4) Working towards fitting tankers with dry coupling counterparts:

The tank farm operator itself has no business relationship with the transport companies delivering the product; it merely acts as a warehouse keeper for a fee.

A letter was sent to the product purchaser asking it to encourage the transport companies delivering the product to fit tankers with dry couplings, in order to increase safety during transhipment and prevent releases of product.

5) Informing offices in the parent company:

The relevant offices of the parent company (international group) have been informed. The incident and possible solutions are being evaluated to prevent similar occurrences.