SAN DIEGO - Nearly 70 children had their blood tested for possible poisoning Thursday and one tested positive, according to the San Diego Housing Commission.

The free testing program at the San Diego Head Start office was part of a weeklong series of events to publicize the issue.

According to the city Environmental Services Department, more than 300,000 structures built in San Diego before 1978 could pose a poisoning risk because of lead-based paint.

"We're very fortunate in San Diego to have federal funding to sponsor a program for families who may be unaware that their children may be suffering from lead poisoning," said Richard Gentry, commission President and CEO. "Since 2010 we have helped test 384 children. These early tests are critical for protecting their health and safety."

Of those 384 children, eight of those tested positive, according to the housing commission. Families of kids who test positive are referred to clinics for follow-up tests and medical evaluations, and are provided information on how to eliminate lead hazards from their homes.

The city has a website at SDHealthyHomes.org with information about lead exposure.

The Centers for Disease Control and Prevention determined recently that there is no safe level of lead exposure for children, according to the city.

Medical evidence shows that even very low levels of lead exposure can have a significant detrimental impact on a child's ability to learn.