CINCINNATI — A spokesman for the company that is the main owner of a pipeline that leaked oil in the area of a southwest Ohio nature preserve says an estimated 240 barrels were released.

The Mid-Valley Pipeline Co. pipeline runs nearly 1,000 miles from Texas to Michigan and is largely owned by Sunoco Logistics. A Sunoco spokesman says the cause of the leak is under investigation.

Authorities say the pipeline has been shut off and the leak contained. An Ohio Environmental Protection Agency spokeswoman says a wetland of about one acre was affected by oil that went about a mile down an intermittent stream.

Authorities say nearby residents aren’t in danger from the leak reported Monday night.

There were no reports immediately of injuries to wildlife at the Oak Glen Nature Preserve.

First Published March 18, 2014, 12:32 p.m.