Among recent examples:

At a Massachusetts drug lab, a chemist was sent to prison after admitting that she faked the results in perhaps tens of thousands of drug cases, calling into question thousands of drug convictions that ended with people in prison.

In St. Paul, Minnesota, an independent review of the crime lab found “major errors in almost every area of the lab’s work, including the fingerprint and crime scene evidence processing that has continued after the lab’s drug testing was stopped in July. The failures include sloppy documentation, dirty equipment, faulty techniques and ignorance of basic scientific procedures … Lab employees even used Wikipedia as a ‘technical reference’ in at least one drug case … The lab lacked any clean area designated for the review and collection of DNA evidence. The lab stored crime-scene photos on a computer that anyone could access without a password.”

In Colorado, the Office of the Attorney General documented inadequate training and alarming lapses at a lab that measured the amount of alcohol in blood.

In Detroit, police shut down their crime laboratory “after an audit uncovered serious errors in numerous cases. The audit said sloppy work had probably resulted in wrongful convictions, and officials expect a wave of appeals … auditors re-examined 200 randomly selected shooting cases and found serious errors in 19.”