Chemical explosion in Spanish petrochemical plant in Tarragona

A chemical explosion at the petrochemical plant of La Canonja, in the town of Tarragona, left both the residents and the authorities in a great state of panic with 2 persons already found dead. The cause of the explosion is still unknown, and the firefighters are still investigating to clarify what type of failure (human or technical) may have triggered this incident.

A few hours after the explosion, Civil Protection advised citizens in nearby municipalities to "confine themselves to their homes" for greater safety. The next morning, the confinement was lifted as no danger of airborne toxins was detected. However, the possible toxicity continues to be of concern to many.

What substances are handled at this petrochemical plant and what is their toxicity? To what extent can they be dangerous? Two experts from the Universitat Rovira i Virgili in Tarragona answer 5 questions that you will probably be asking yourself after the incident...

1. What happened?

At around 18:41 on Tuesday 14th January, an explosion took place in the petrochemical plant in the La Canoja industrial estate in Tarragona.

According to official sources, there was an explosion in a reactor, which affected a tank containing a hydrocarbon called ethylene oxide, a highly flammable material.

At the moment the fire continues and there are still burning products in the tank. Firefighters say that the fire is under control, and they continue to cool the tank regularly in order to keep it under control.

2. What is a petrochemical plant?

The petrochemical industry produces raw materials from hydrocarbons, such as oil or gas. These raw materials are used to manufacture materials that we humans use for our infrastructure; for example, paint, PVC vinyl chloride, rubber styrene and different types of plastics.

Petrochemical plants require complex facilities for the combustion of these hydrocarbons, including, broadly speaking, reactors that raise the substances to enormous temperatures and tanks for their storage. 

3. What is ethylene oxide?

The petrochemical plant that has exploded works with ethylene oxide, a very light hydrocarbon with a low molecular weight and therefore highly flammable.

According to Xavier Farriol, Professor of Analytical Chemistry and Environmental Pollution Risks: "Although it is a highly flammable material, it is not such an exotic product, nor is its use at all unusual".

In this type of industry, ethylene oxide is worked at very high pressure and temperatures. Its uses are very diverse: as antifreeze, to manufacture many types of polymers, and as a disinfectant in the pharmaceutical industry, in textiles...

4. Is it carcinogenic? What is the risk of toxicity?

The expert clarifies that ethylene oxide is classified as "probably carcinogenic", but "only in very long exposures, and in very charged atmospheres". To top it off this substance would be irritating on direct contact. "I do not believe there is any risk to firefighters who are extinguishing the fire."

On the other hand, the authorities have reported that there is no toxic cloud in the environment, so there would be no risk for the neighbouring population either.

"We are facing a very serious accident,  but it is serious because of the explosion and the fire, which is toxic in itself. We're not talking about dangerous toxicity produced by the chemicals in the plant," declared Farriol. "The toxicity is what you would expect, the toxicity of a fire, but in no way are we talking about a kind of Chernobyl, not even on a small scale.

Francesc Castells, Emeritus Professor of Chemical Engineering, also believes that the gases emitted by the explosion and the current fire "should not be especially toxic to the firefighters or to the nearby population". 

5. What safety measures does a petrochemical plant have in place?

La Canoja is a petrochemical plant that was inaugurated in 1966 (by Francisco Franco) and was the first plant of these characteristics in Tarragona, being a pioneer in Spain. This plant has changed hands several times and is now owned by the company IQOXE (Industrias Químicas del Óxido de Etileno). In spite of its age, approximately one year ago it was thoroughly renovated, so all the safety measures should be updated.

For Francesc Castells: "Safety levels in petrochemical plants in Spain are high; though, of course, they are never zero, and there is always room for improvement. All industrial activity involves some risks, even if they are minimal. But, in my opinion, they are bearable. The alternative would be to stop manufacturing these products.