Buenos Aires fought a ferocious -- and expensive -- legal battle against Uruguay two years ago in a bid to have the Finnish-built pulp mill closed down, taking the case to the International Court in The Hague, Netherlands. The world court rejected Argentina's claim that the facility pollutes the river.
Argentine officials say Uruguayan plans to increase the plant's capacity change everything, including the basis for the court's judgment in favor of Uruguay. With more pulping activity envisioned, the plant will be operating in violation of bilateral agreements and international conventions, the complaint says.
Critics, including some in Argentina, argue the revival of a growing protest movement against the pulp mill is a politically motivated ploy by President Cristina Fernandez to win popular approval before October mid-term elections.
The pulp mill produces about 1.1 million tons of cellulose paste each year, mainly for export. The plant's Finnish operators want to raise that capacity to 1.3 million tons. Argentine officials said the planned increase will put pollutants in the Uruguay river, a charge both the pulp mill management and the government in Montevideo deny.
Controversy over the Uruguayan plans hit the headlines after Argentine Entre Rios province Gov. Sergio Urribarri launched highly publicized protests.
Urribarri said he is seeking clarifications from Uruguay over the pulp mill expansion plans. Despite independent international assessments the pulp mill isn't a threat to the local environment the Argentine government says the expansion threatens to break bilateral agreements on the conduct of both sides on key environmental issues.
Senior Argentine officials said Uruguay's action was "shameful" and an affront to existing understandings over pollution control.
Uruguayan President Jose Mujica, who helped defuse a previous diplomatic row, has declined to become entangled in the argument. He suggested Argentine protests were tied to that country's mid-term elections Oct. 27 and any action before those polls would be unnecessary.
Mujica is treading carefully on the pulp mill dispute after recent economic setbacks hit his public approval ratings.
Mujica, 77, came to power amid optimism his easy-going patrician style of governance would boost business confidence, stabilize Uruguayan society and make the most of the country's commodities-driven income growth.
Instead, critics of Mujica complain most of the country's economic and social problems remain unresolved and runaway inflation is taking a toll on Uruguay's living standards. The pulp mill dispute comes at an unwelcome juncture for Mujica.
Mujica won international respect after he persuaded Fernandez to drop her confrontation with Uruguay over the pulp mill dispute. But the country's ties with Argentina soured again as Montevideo tried unsuccessfully to resolve differences over border tariffs, disputes over the use of waterways and other trade issues. The pulp mill row has spawned several new political groups in Argentina, drumming up support for Fernandez but also engendering environmental politics in the country.