Lindane, a pretty name for a poison

Great means for great challenges: with considerable help from the Cohesion Funds, the Basque government has undertaken to clean the numerous industrial sites contaminated by lindane.

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The Argalario isolation zone under construction: 412 000 m³ of contaminated earth is isolated from the environment. The Argalario isolation zone under construction: 412 000 m³ of contaminated earth is isolated from the environment.


Forty years of bad industrial practices in the production of a pesticide, lindane, have left the Basque Country with a poisoned heritage: 82,000 tonnes of dangerous waste, of which 5000 tonnes is largely pure and stockpiled in two closed-down factories and 77,000 tonnes is dispersed in an uncontrolled manner over 33 sites totalling some 560 000 m³ of contaminated land. Lindane, a hexachlorocyclohexane (HCH) compound, is dangerous for the environment and classed as a potential carcinogen and endocrine disruptor. It contaminates soil, ground water and watercourses and is diffused into the atmosphere as a vapour or in association with dust particles. It then makes its way into the food chain. The EU decided to outlaw its agricultural use in 2003.

After studies in collaboration with the University of the Basque Country, the regional public company for environmental management IHOBE was entrusted by Basque Country government’s Department for regional development with implementing a huge clean-up project from 1995 onwards.

Isolation of contaminated land

Technically speaking, the solutions chosen, on the basis of available technology and size of operations, included the construction of 2 isolation zones.

The first (150,000 m³) was set up at Loiu near Bilbao airport, and the second (412,000 m³), constructed with the help of the Cohesion Funds, on Mount Argalario in Barakaldo, a region on the left bank of the Nervión-Ibaizabal river. Their development required tens of thousands of trips by special container trucks bringing polluted earth from the different sites. The objective: to stop contamination and hold the effluent with a view to later treatment. Consisting of mineral and synthetic materials (including high density polyethylene) they have been constructed according to international norms with all the measures required for technical inspection and health and safety.

Elimination of pure HCH

The other key element in the project is the elimination of pure HCH. To this end, the Basque authorities obtained, in 1992, a license to use the base catalysed dechlorination process (BCD) in the region from the American environmental agency. This process destroys HCH at a temperature of 150° by means of a chemical reaction which converts it to sodium chloride (salt), trichlorobenzene (TCB) and water. Prior to the inauguration of the treatment station, at Barakaldo in 1999, research had maximised the efficiency of the reaction to attain a conversion rate of 99.9995% on a throughput of one tonne per hour. Also cofinanced by the Cohesion Funds, the station was constructed near the stockpiles to limit the risks of transporting the product. It was the subject of rigorous environmental scrutiny.


The isolation of contaminated earth saved the ecosystem from accumulated degradation while stimulating socioeconomic development in the region by improving the life of its inhabitants and making it more attractive to businesses.

As for the treatment of pure HCH, in its two years of operation before its decommissioning in 2001, the station eliminated 3,200 tonnes of lindane. This process permitted the recycling of 1,074 tonnes of TCB, distilled and commercialised as a primary material for the chemical industry without the difficulties associated with its other methods of production. Likewise, the salt resulting from the conversion of the HCH was purified and used for the production of brine. The residue (containing earth, gravel, mixed impurities) was transferred to the isolation zones.

In employment terms, the construction of the Argalario zone mobilised around 200 people and the HCH treatment created 20 jobs directly and over 100 indirectly (suppliers etc.).

Draft date