SAN FRANCISCO (Reuters) - A California-based workers advocacy group released a report on Wednesday saying that Tesla Inc TSLA.O data showed its workers have been injured at a rate a third higher than the auto industry average.

FILE PHOTO: A Tesla logo hangs on a building outside of a Tesla dealership in New York, U.S., April 29, 2016. REUTERS/Lucas Jackson/File Photo

Worksafe made the analysis after being approached by the United Auto Workers, the Detroit-based union that has been talking to Tesla employees about organizing. (bit.ly/2qQs8dv)

Tesla is the only U.S.-based automaker without union representation.

Tesla responded to the report by saying its accident rate in the first quarter of 2017 was 32 percent better than the industry average.

“We may have had some challenges in the past as we were learning how to become a car company, but what matters is the future and with the changes we’ve made, we now have the lowest injury rate in the industry by far,” said Tesla in a statement.

One change was adding a third shift, which Tesla said led to a 30 percent drop in recordable incidents in the first quarter of 2017 from a year earlier.

Worksafe said the first-quarter data was preliminary and not enough to show a trend.

Tesla said in a May 14 blog that the union was using questions about safety as part of an organizing drive. (bit.ly/2rk1E1F)

The UAW, which put the report on the front page of its website, declined comment.

The report comes at a critical time for the Silicon Valley luxury carmaker, which is preparing to launch its Model 3 sedan, hiring and ramping up its factory for a six-fold increase in volume next year.

Worksafe Executive Director Doug Parker told journalists in a briefing that the group met with Tesla factory workers after being approached by the UAW. Worksafe engages in campaigns with unions and other groups.

The Worksafe analysis of Tesla injury logs sent to California health and safety regulators showed that the carmaker had 8.8 injuries per 100 workers in 2015, 31 percent higher than the U.S. automotive industry mean of 6.7.

The figure, called a “total recordable incidence rate” (TRIR) fell to 8.1 injuries per 100 workers in 2016, for which industry-wide data is not yet available.

Worksafe also calculated that the rate of serious injuries known as “days away, restrictions and transfers” was double the industry rate in 2015 and fell slightly the next year.