Our environmental interventions in Pieve Vergonte

We are realising one of our most challenging remediation projects that will engage us for the next years.

Pieve Vergonte, our commitment for the requalification of the site

Pieve Vergonte is one of Italy's oldest production sites, nestled between the Piedmont Alps and Lake Maggiore in the Ossola Valley. Since 1915, the small farming town has been at the forefront of a century of industrialisation. Its origins are linked to the Chimica Dott. Vitale company, which produced chlor-alkali, sulfuric acid, and fertilisers, and later to other activities to support the war industry. Over time, DDT and chlorine derivatives were also produced. Eni has been operating in Pieve Vergonte since 1982, with the acquisition by law of the Sir Rumianca group through its subsidiaries Anic and subsequently Enichem Synthesis, as part of the site industrial rescue operation ordered by the State. The first environmental interventions date back to 1995, with the beginning of environmental investigation of the soil and groundwater, which were subsequently included into the Characterisation Plan that was approved in 2003.

Afterwards, emergency safety measures were implemented, the decommissioned facilities were demolished, a barrier for the site's hydraulic containment was constructed, and the groundwater treatment plant (GTW) was upgraded. Today, the chlor-alkali plant and the chlor-aromatic lines managed by Esseco Group are operational. In the remaining decommissioned areas (37 hectares), as owners and holders of remediation costs, we continue to carry out soil and groundwater interventions. As of 31 December 2024, we have incurred environmental costs amounting to €276 million.

Pieve Vergonte: key elements

We adopt sustainable and circular solutions for the protection of natural resources

Sustainable and circular solutions to preserve soil resources

For the remediation of the site’s soil, we favor sustainable and circular solutions that include on-site technologies to minimise soil movement and enable its recovery.

Water conservancy

At the site, we manage groundwater remediation with a hydraulic barrier consisting of 40 pumping wells and a water treatment plant among the largest in Europe with a capacity of 1,250 m³/h.

Pieve Vergonte at a glance

Location: Italy, Piedmont

Start of the environmental interventions: 1995

Pieve Vergonte past and present

Site history.

Esseco Group enters the site

Esseco Group takes over Hydrochem Italia's productions, managing the chlor-alkali plant and the chlor-aromatic lines still active.

Closure of the DDT, Chloral and chlorosulfonic acid plants

Once the DDT plant was closed, followed by chloral and chlorosulfonic acid lines, residual productive activities were sold, with surface rights on the areas, to Tessenderlo, then to Hydrochem Italia.

Start of the first environmental interventions at the site

The first environmental interventions date back to 1995 with the start of soil and groundwater environmental investigations, which were then included in the Characterisation Plan approved in 2003.

Transfer by law of production activities to Anic

The productive activities were transferred to Anic (Eni group) pursuant to law n. 784/80 and later to EniChem Synthesis (1984).

Our story

The plant ownership goes to Sir-Rumianca

The plant is first transferred to the Snia company (1920) and then to the SIR-Rumianca group (1924).

Establishment of the industrial site

The plant was built between 1915 and 1920, with the commissioning of an electrochemical plant. At the time, the chemical company Dott. Vitale produced chlor-alkali, sulfuric acid, and fertilisers.

Our activities in Pieve Vergonte

At the Pieve Vergonte site, we are remediating the soil by addressing multiple matrices with targeted environmental interventions, designed to also minimise soil movement. The remediation project, approved in 2013, envisions a circular and sustainable solution: compliant soil will be used for backfilling, while the unsuitable portion will be confined to a facility, isolated from the outside environment and purposely constructed on-site, which will be developed in subsequent lots and, once the interventions are completed, will be replanted with native vegetation. In 2025, following the authorisation of the remediation project variant, we began the activities for the restoration of the Marmazza river to its natural course. This operation will later allow to carry out the soil remediation activities with hydraulic safety, preserving groundwater resources. For groundwater treatment, a hydraulic barrier is active with approximately 40 pumping wells that send water to a GTW plant, one of the largest in Europe, capable of handling up to 6 billion litres per year. In-situ remediation interventions are also underway on the main contamination areas, using Air Sparging (AS) and Soil Vapor Extraction (SVE) technologies.

Grounds deposit

The restoration of the Marmazza river to its natural course. A challenging project meant to make history in environmental engineering in Italy.

At the Pieve Vergonte site, we are realising one of the most challenging and complex projects: the restoration of the Marmazza river to its natural course. This intervention is propaedeutic to soil remediation activities, as it prevents the risk of flooding at the site and surrounding areas in the event of heavy rainfall. This impressive hydraulic work concerns a stretch of the river that is over 1km long, diverted into the site in 1918 to meet the water needs of industrial activities. Cutting-edge civil engineering technologies will be deployed to overcome the riverbed's interference with the Sempione highway, the Gottardo railway and the hydroelectric canal, ensuring the continuity of essential, uninterruptible services. For the safety of the area, the Toce river embankments will also be restored and reinforced at and downstream from the Marmazza river's inflow point.

Geoarte project

As part of the environmental interventions at the Pieve Vergonte site, we promoted the Geoarte project, an initiative to support the safeguarding and valorisation of the area's archaeological heritage in collaboration with local institutions. The study, which involved a series of geoarchaeological surveys conducted by Ca' Foscari University of Venice, helped identify remediation design solutions that fully respect the area's archaeological heritage while also minimising potential interference.

Status of the environmental process

The operative remediation project for the site was authorised in 2013. In 2018, the company submitted a project variant that was later divided into two phases: Phase 1 was approved in 2024, the request regarding Phase 2 will be transmitted for approval by December 2025.