The father of two toddlers who drowned in a Warren County wastewater pond in 2005 contends in a civil lawsuit that the city of Warrenton and its former sewage-treatment contractor are responsible for the deaths.

The complaint filed in Fulton County by Dennis Payne alleges that workers ignored holes in a safety fence around the city-owned pond where the bodies of Jonah Payne, 3, and his 2-year-old sister, Nicole, were found in April 2005.

Mr. Payne, who is seeking a jury trial, did not specify damages in the 21-page complaint, but a legal notice sent to city officials before the filing of the lawsuit mentioned $10 million per child.

The children's mother, Lottie Payne - who is not mentioned in the lawsuit - was found criminally responsible for the children's deaths last fall after a weeklong trial in which she was convicted of second-degree cruelty to children. She is serving a five-year prison term.

During her trial, prosecutors characterized her as an unfit mother who repeatedly neglected and did not protect or supervise her children. She was convicted after 58 minutes of deliberation.

Mr. Payne's lawsuit accuses city officials and the city's former contractor, Operations Management International, also known as OMI, of causing the children's deaths.

The safety fence surrounding the pond had holes in it, and the entrance gate was improperly locked, the complaint alleges.

The city also was warned by state environmental regulators that the gates were not properly secured and that warning signs were not posted in the area.

The complaint also alleges that - eight days after the children's bodies were recovered - Warrenton officials held a closed-door meeting to discuss their liability and later authorized $20,000 to correct safety deficiencies.

"Defendants' failure to maintain a safe and effective fence; failure to monitor the subject premises, failure to safely secure gates, failure to remove thick algae which created the appearance of solid ground and other breaches of care proximately caused the injury and untimely deaths of Jonah and Nicole Payne," the lawsuit contends.

A lawsuit represents one side of a dispute.

The city and the legal team that represents the city's insurance carrier are preparing a response, said Warrenton City Attorney Samuel Fowler Jr.