LONDON (Reuters) – Lawyers representing claimants taking legal action over Brazil’s worst environmental disaster filed an injunction this week against miners BHP and Vale for “trying to derail” a potential 36 billion-pound ($46 billion) London lawsuit.

More than 720,000 Brazilians, including 46 local governments, are suing BHP and Vale over the 2015 collapse of the Mariana dam, which was owned and operated by their Samarco joint venture.

The dam collapse caused a wave of toxic tailings that killed 19 people, left hundreds homeless, flooded forests and polluted the entire length of the Doce River.

Brazilian Mining Association IBRAM filed a motion in Brazil’s Supreme Court on June 11 seeking to stop around 46 municipalities from continuing in the London case on the grounds that doing so represented a threat to Brazil’s sovereignty.

BHP and Vale are both members of IBRAM and the claimants allege they asked IBRAM to make the claim at the Supreme Court.

BHP, the world’s biggest miner by market value, declined to comment. Vale also declined to comment.

“The duplication of lawsuits, in Brazil and abroad, affects all industries in the mineral sector and companies in other sectors that are being targeted by this type of litigation,” IBRAM said in an emailed statement.

“Situations like these create legal uncertainty, harm the business environment and the Brazilian economy,” it added.

The 46 municipalities would account for at least 4.47 billion pounds of the London lawsuit, the injunction application shows.

“Whilst removing the municipalities wouldn’t stop the case, it’s quite a substantial interference with the way that the group claim is structured, but also … the court in England has already taken jurisdiction over this,” Tom Goodhead of law firm Pogust Goodhead, which represents the claimants, said.

“What we’re seeking is an order from the English court that they be forced to try to withdraw the claim before the Supreme Court in Brazil,” he said.

The London lawsuit is separate from litigation in Brazil, which mostly addresses claims from local governments and not individuals, Goodhead said.

The lawsuit, one of the largest in English legal history, began in 2018. The first trial of key legal issues is due to begin in October.

Vale, BHP and their joint-venture Samarco earlier in June presented Brazilian authorities with a $26.09 billion offer to settle reparations for the dam collapse after Brazil rejected a previous offer.

BHP, which denies liability, has referred to reparation and compensation programmes implemented by the Renova Foundation, a redress scheme established in 2016 by Samarco and its shareholders, which has funded more than $6 billion of rehousing, rehabilitation and indemnification for those affected by the disaster.

Vale has previously said it “reaffirms its commitment to repairing the damage caused by the Fundao dam collapse”, under agreements with the Brazilian authorities.

($1 = 0.7901 pounds)

(Reporting by Clara Denina; additional reporting by Sam Tobin and Kirstin Ridley. Editing by Jane Merriman)