California officials received a number of bad results from a forensic lab, who's double checking the results in our country's forensic labs?

Retesting of dozens of tests done by a Chatsworth forensics laboratory ---- tests feared to be faulty ---- have not turned up any more botched findings, San Diego County prosecutors said this week.
The review came after tests from Pacific Toxicology in Chatsworth returned a number of incorrect results in San Diego County criminal matters, including a false positive finding of morphine in the system of one juvenile suspect charged after a deadly crash in Rancho Santa Fe killed a teenager.
Pacific Toxicologies is a private forensic laboratory that tests evidence in many drug- and alcohol-rated cases for law enforcement agencies.
Prosecutors often use the results of such tests in criminal cases; bad lab tests raise fears of wrongful convictions.
It is the second time in a year that criminal cases in San Diego and Riverside counties have been hit with concerns about the potential for bad lab results.
The problems at Pacific Toxicologies, commonly referred to as Pac Tox, followed concerns early last year involving an unrelated Riverside laboratory that led officials to question and subsequently retest thousands of cases.


Link:
http://www.nctimes.com/news/local/sdcounty/article_c3203045-8c4b-5769-aca3-4e6083b01a38.html