Nikola has recalled all of its electric trucks it has delivered so far and suspended sales after an investigation into recent fires revealed a coolant leak inside the battery, Reuters reported.

A total of 209 Nikola electric trucks are currently on the market with dealers and customers, and the company is recalling the vehicles and is in the process of contacting all parties, a Nikola spokesman told Reuters.

Preliminary findings from an investigation by a third-party investigator were confirmed Thursday by a “minor thermal incident” in the battery of a truck parked for a technical inspection, the company said, adding that no one was injured.

“It is unlikely that malicious activity or other external factors caused the incident,” Nicola said in a statement, adding that efforts were being made to provide a legal remedy.

The company said it suspected foul play in June when it began an investigation after trucks caught fire at its plant in Phoenix, Arizona.

Last month, a damaged truck that had been stored at the Phoenix plant for observation caught fire again.

Internal investigations by Nikola’s safety and engineering teams indicate that a single supplier component in the battery pack is the likely source of the coolant leak that caused the vehicles to catch fire, the company said.

Big problems for Mykola

Struggling with supply chain bottlenecks and weak demand, Nikola decided to build electric trucks only to order and focused on hydrogen fuel cell trucks.

On Aug. 4, Nikola appointed Stephen Girsky, former CEO of General Motors, as chairman, its fourth in four years.

The company expressed “substantial doubt” about its ability to continue as a going concern over the next 12 months, repeating the warning for the third time since February, as it expects “significant” additional capital.

On Friday, Nikola asked customers and dealers of its electric Tre trucks to immediately take certain safety measures, including the ability to park them on the street.

Nikola shares fell 5.6% after the stock market closed.