VERNON, Vt. -- Human error is being blamed for a radiation spike at the Vermont Yankee nuclear plant that prompted the evacuation of about a dozen workers from the main reactor building for about two hours.

Radiation Spike Is Latest Black Eye At Vermont Yankee

Plant spokesman Robert Williams said a worker did an incomplete job clearing water off of a demineralization filter during routine monthly maintenance. A short time later, control room operators spotted the doubling of radiation levels in a main steam line.

Williams said there were no radioactive releases to the environment, and that the plant's operations and power level were not affected.

Tuesday's incident remains under investigation.

Vermont Yankee has been under increasing scrutiny from lawmakers and environmental critics due to the plants spotted safety history, which includes several problems at the plant in the past year.

Click Here For Timeline From Brattleboro Community Brain Trust

New Hampshire Congressman Paul Hodes and state Senator Molly Kelly said they have gotten some answers about safety at the Vermont Yankee Nuclear plant, but want more.

Hodes and Kelly met with federal officials last month to discuss recent safety incidents at the plant, which is just over the New Hampshire border.

They asked the NRC for a description of how it notifies New Hampshire federal and state officials of incidents, for documents on several incidents and information on what is being done to ensure the water cooling system is safe.

Hodes released a letter from the NRC outlining notification and giving details of several incidents.

The NRC said it has been monitoring and inspecting the plant's cooling towers since a problem last August and a leak in July.