The families of Beirut port blast victims have filed a lawsuit against US firm TGS Nopec Geophysical, owner of British firm Spectrum Geo for its suspected links to the Ammonium nitrate-carrying ship Rhosus. 

The probe was filed this week in Texas against the US-Norwegian geophysical services group TGS.

Families of the Beirut port blast victims accuse Spectrum of "negligence that resulted in the death of their loved ones”.

Meanwhile, the prosecutors hope that Spectrum's exact role in the explosion will be clarified.

The explosion was described as one of the largest non-nuclear explosions in recent history, killing over 200 people, injuring thousands, and destroying entire neighborhoods.

The complaint accuses Spectrum of chartering the Moldovan-flagged Rhosus in 2013 to sail to the port of Beirut, a dilapidated boat containing hundreds of tons of nitrates originally intended for Mozambique.

While the ship was not supposed to head to Beirut, Spectrum sent it there to retrieve a large amount of seismic analysis equipment, and as soon as it arrived, it began loading 160 tons of seismic survey equipment that the Lebanese authorities had allegedly previously requested.

The ship unloaded the ammonium nitrate and stored it in the Beirut port because the extra load could permanently break and damage the boat. The nitrates were left there for seven years.

The complaint says that chartering a boat that is "recklessly unseaworthy and carrying explosives without the necessary permits, is a violation of individual contract terms, local law, and industry best practice, and is ultimately responsible for this horrific explosion."

The cataclysmic explosion occurred when the remaining 2,750-tonne stock of ammonium nitrate left by Rhosus seven years earlier caught fire.

It is still unknown what caused the fire.

The nine plaintiffs are all US citizens and include Sarah Copland, the mother of two-year-old Isaac Copland, who was one of the explosion's youngest victims.

Ford O'Brien Landy LLP is the lead counsel in the "strict liability" case, and Accountability Now's lawyer Zena Wakim said TGS' response should be known "in the coming months."

"The evidence that will be generated by this lawsuit can also benefit the Lebanese investigation," Wakim said as quoted by AFP. 

"The spirit of the claim is to benefit all the victims," she added.

Two years after the explosion, one of the victims, lawyer Tania Abu Alam, was quoted in Swiss newspaper Le Temps as saying: "There are a lot of gray areas. Why did Spectrum hire the Rhosus (the cargo-carrying ammonium nitrate) to transport earthquake machines when it was a death ship? ".

Abu Alam questioned the reason behind the company’s decision to choose this particular ship from among all available ships, despite the fact that it was already at 300 percent of its maximum allowable capacity, with 2,750 tons of explosives on board, flying the Moldovan flag, and lacking the ramps required to transport the alleged seismic machinery."

Read more: “Truth Uncovered": Al Mayadeen's Exclusive Documentary on Beirut Port Blast