This incident did not occur on an industrial site, yet it had an important bearing on industrial safety, because of the very high number of casualties and the fact that it involved an industrial product during transportation.

A road tanker was filled with liquefied propylene at the Enpetrol Refinery in Spain, at round 12.00 noon on 11th July, 1978. While the capacity of the tanker was approximately 19 tonnes (which allowed for 20% ullage), the tanker was apparently filled to its full capacity of 23 tonnes. As the tanker began the journey to its destination, the temperature of the contents of the tank began to increase slowly, and the resultant expansion of the liquid put the container under strain. After about 2.30 hours of the journey, and 102 kms of travel, the tanker suddenly disintegrated. It is believed that the temperature had by that time risen to approximately 23ยบ C. At that moment (approxmiately 2.30 p.m.), the tanker was passing through a popular holiday camp called Los Alfaques,where around 500 people were present.

As a result of the disintegration, the tanker (bullet) broke off into two major parts, and a number of smaller fragments, some of which travelled upto 300 mtrs. the tanker fragments, which were propelled with great force, also destroyed structures in its path. The failure of the tanker resulted in the release of the liquid propylene, which flashed to vapour. Due to the travel of the tanker fragments, the liquid was sprayed out over a large area, resulting in spread of the flammable vapours. Almost immediately, the vapours ignited due to an unknown source, resulting in a very large flash fire. This led to the generation of an extreme heat wave, which killed almost all people in its vicinity. The final toll - 215 dead, almost all burnt to death, and approximately 61 severely injured.

San Carlos incident - effects and consequent safety upgradation

Such large casualty figures were unusual for any accident, whether inside or outside industrial premises, and galvanized the authorities into action. A number of studies, both statutory and private were carried out of the incident, and important changes were implemented. Some of the important aftereffects of this incident were that regulations regarding transportation of chemicals became more specific and detailed, and began to be more rigidly implemented. For developing countries, once again it brought the focus on the hazards of transportation of dangerous goods, and as a result, various changes were implemented. The provision of Safety valves and other safety features for different modes of transport now became mandatory. Training of drivers of such transport vehicles in safety aspects, and the carrying of TREM (TRansport EMergency) cards with the vehicle transporting the chemical, became mandatory.

It was also obvious that the supervision of the loading at the Refinery had left a lot to be desired, and industry personnel began to view this operation of the industry seriously, with stricter codes of practice being implemented. The unusually high number of casualties once again brought the focus on the flammability properties of liquefied flammable gases, and risks involving handling and transport of the same.