LOS ANGELES - A government contractor's omission has put hundreds of Los Angeles County adoptions into question, leading to a scramble by officials and child advocates to make sure they are legal.

It was discovered in June that Yoakum Investigations, which has a $549,000 contract with the Department of Children and Family Services, failed to properly notify birth parents or guardians in 237 cases in which foster children were up for adoption.

Written notice is required by law in adoption matters to ensure the delivery of subpoenas, notices and other legal documents pertaining to court hearings.

Child welfare officials immediately halted use of Yoakum Investigations, which has led to delays in some adoptions and caused county lawyers to put in thousands of extra hours to correct the problem.

Chief accountant-auditor Michael McWatters said a meeting was planned later this week with the firm's Alice Yoakum. A man who answered the phone at Yoakum Investigations declined to comment Tuesday.

Lawyers from the county counsel's office, Alliance for Children's Rights and Public Counsel of Los Angeles have been meeting with Juvenile Court Presiding Judge Michael Nash.

"We've gotten together with all the stakeholders," Nash said Monday. "The only thing we can do at this point is to provide notice to the potentially aggrieved parties so they understand what happened or didn't happen, and, if they need to go back to court, they will have the opportunity to be heard. It's fundamental due process."

Nash said court officials have found the parties were notified by other means, such as through their social workers or lawyers. The judge said he suspects only a very few cases will be impacted by the lack of notice.

Deputy County Counsel Jim Owens, division chief of the office's dependency section at the Edelman Children's Courthouse, said he has assigned three lawyers to work on the problem.