The Jasper County Sheriff's Office says the blaze late Saturday near Reasnor, Iowa, caused about $2 million damage to an excavator and three bulldozers.

REASNOR, Iowa (AP) - Authorities suspect arson in the latest burning of heavy equipment being used in the construction of the four-state Dakota Access pipeline in central Iowa.

The Jasper County Sheriff's Office says the blaze late Saturday near Reasnor, Iowa, caused about $2 million damage to an excavator and three bulldozers. The equipment is operated by a contractor for Dakota Access, a subsidiary of Dallas-based Energy Transfer Partners.

Opponents have for months been protesting the $3.8 billion, nearly 1,200-mile project pipeline, warning its construction could jeopardize water supply and damage cultural artifacts.

Another suspected arson of construction equipment happened on Aug. 1 at the same site, about 30 miles east of Des Moines.

No arrests have been made in either fire. The Iowa Fire Marshal Division and the FBI are investigating.

The Des Moines Register is also reporting that Dakota Access has offered a $100,000 reward for information leading to a conviction in the incident.

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