By law, California businesses must report any injuries sustained by employees that result in missed work, job performance restrictions or medical treatment beyond first aid. A report at Reveal made the initial claims, and Tesla has repudiated the report itself, saying that it has never intentionally misrepresented its safety record. Whatever the actual story, Cal/OSHA told Bloomberg that it takes workplace hazards and allegations of underreported work-related injuries seriously, and that is why it is investigating.
Update: A Tesla spokesperson tells Engadget that Cal/OSHA is "required" to investigate any injury claims, whether "they have merit or are baseless." It adds that it passed a previous Cal/OSHA investigation with no violations and has never received any violations for inaccurate record-keeping. Its full statement is below.
The injury rate at our Fremont factory is half what it was in the final years of the UAW plant operated by GM/Toyota immediately before us, and we care deeply about the safety and well-being of our people and strive to do better every day. Cal-OSHA is required to investigate any claims that are made, regardless of whether they have merit or are baseless (as we believe these are), and we always provide our full cooperation. Last year, a Cal-OSHA investigation into our injury reporting and record-keeping was closed without any violations found and without any further action taken. In fact, unlike other automakers who in the past have been cited by OSHA for record-keeping violations, we have never in the entire history of our company received a violation for inaccurate or incomplete injury record-keeping.