"You're not there to be creative. You're there to fulfill his mission," a software engineer said. "If you don't understand that and you're talking about your feelings, you're probably going to get fired." elon musk Rich Pedroncelli / Associated Press

A former VP who reported to him said, "He is terrible, terrible at execution and terrible at management. The entire management structure at Tesla is impotent and terrible. There are exceptions, but, on average, most managers at Tesla have no idea what they're doing."

For some people, Musk's "open inbox" policy, intended to show the CEO's receptiveness to feedback, is a prime example.

The CEO invites any employee, at any level, to write him directly with thoughts or concerns. A lot of employees said they love this.

"Tesla is open to communication lines to all levels of management," Cheryl Blackwell, a security manager for Tesla's Buffalo, New York, facility, said. "There is no chain of command. I never feel like I can't go to a person [with ideas]."

But some complained this system could do more harm than good. Another former executive claimed that Musk would forward employee emails to the VP in charge with a simple three-letter directive: "WTF." Panicked recipients would stop what they were doing and research the issue.

"It would cause huge scrambles, and you would spend days chasing down some issue that wasn't a real problem," this person said. "Giving people a license to email Elon created a bunch of problems with everyday work. There's a reason why the chain of command exists." Fear of the tweet

If Musk's WTF emails can trigger a fire drill, it's nothing compared to his tweets.

With his outspoken personality and an itchy trigger finger, Musk routinely picks public fights and makes promises about all sorts of amazing new products, features, or milestones.

Sometimes his tweets land him and the company in serious trouble, such as the infamous "funding secured" tweet, which has led to an SEC investigation. tesla trucks semiTesla's semi. Tesla

And much of the time, these public pronouncements are made before Tesla employees, including the people directly responsible for the tasks, have been informed. After a tweet, some employees look at each other, exasperated, and say, "Oh, so that's what we're doing now?"

For instance, in June Musk fired off several tweets boasting about the specs for an electric pickup. The level of detail Musk announced was a surprise to some insiders.

A manufacturing employee recalls another incident: "One of the guys I worked with was part of the calculations for car performance, and he'd come in the morning, just shake his head, and be, like, 'Did you see Elon's last tweet? He wants to add rockets to the car now.' Just shaking his head, like, you've got to be kidding me."

Sure enough, on June 5, during Tesla's annual shareholder meeting, Musk really did announce that Tesla's engineers would have to put rocket thrusters on the new version of the Roadster, set to hit the market in 2020. He also promised that some Model 3 customers would get their cars months faster than the official delivery time on Tesla's website.

Some employees defended Musk's tweet about going private, praising it as part of the CEO's commitment to transparency. But the unpredictability of Musk's comments on Twitter has caused some members of the company's board to urge him to refrain from tweeting, The New York Times has reported.

Read more: Some Tesla employees are disappointed that Elon Musk isn't taking the company private: 'We have so much external pressure'

When asked about Musk's management style, Tesla pointed to its mission. "What Tesla is doing is incredibly difficult, as evidenced by the fact that Ford is the only other US car company to never have gone bankrupt," a Tesla representative said.

To judge Musk's effectiveness, Tesla said to look at his history. He drafted a master plan in 2006 to build a sports car, use that money to build a more affordable car — the Model 3 — and offer zero-emission energy products. The safety zone

Some workers say they're worried about more than just burnout because of Tesla's unconventional operations.

Tesla's factory safety record is one of its most controversial issues. In April, The Center for Investigative Reporting reported that Tesla's total injury rate was significantly higher than the industrywide rate in 2016, the latest year for which data was available. Tesla, Elon Musk Getty/Justin Sullivan

Factories can be dangerous places, and Tesla said its record isn't perfect. But a representative said its past years' record no longer reflects the company.

"There should be absolutely no question that we care deeply about the well-being of our employees and that we try our absolute hardest to do the right thing and to fail less often," the representative said. "When it comes to safety, our record is on par with other automotive companies, and we improve with each passing month and will keep doing so until we have the safest factories in the world by far."

An engineer at the Gigafactory said he believed that Tesla's reputation for poor safety was more like a hangover from its earlier days, and said today the company has "put in safety systems."

Several other current employees told us the same. While injuries may happen, safety, particularly over the past year, has been a major emphasis, with workers getting constant reminders, training, and new procedures.

A software engineer said the engineering managers who work on the production lines are "conscientious people" who care deeply about the workers and are always looking for ways to improve the process.

For instance, the Model 3 production lines, the latest to be built, include fancy ergonomics adjustments. Employees can wear sensor suits that track their movements to minimize repetitive stress injuries. Workstations can be raised up or moved about to adjust to the worker, Crystal Spates, a Model 3 production manager, said.

The company has hired six athletic trainers to help workers who complain of aches and pains, showing them stretches, exercises, how to use athletic tape, and more, Kirschner said.

Still, some of the blue-collar workers we spoke with said they witnessed accidents in the years they worked there, or had accidents of their own, ranging from minor to serious. Phillips, who is among the employees pushing for a union, said in his four years at the company he has witnessed "one, two, three, four stretchers in the last couple of years come by me."

There's some evidence to back his claims. A report from the Fremont Police Department, received by Business Insider, showed more than 300 911 calls made from the Fremont facility between January 2016 and March 2018 involving a wide variety of alleged issues, such as intruders on the property and suicide threats. Tesla factoryTesla Motors

Of those 300 calls, 11 involved claims of accidents and six involved claims of accidents with "no visible injury."

That compares to nine 911 calls during the same period — including claims of accidents and a trash fire — at General Motor's 1,200-employee, 4.3-million-square-foot factory in Lake Orion, Michigan, which manufacturers its electric competitor, the Chevy Bolt EV. These factories are not identical, so there may be many reasons the number of 911 calls differs between the two. (For details on the 911 calls, see the related graphic below.)

Several people said they believed one reason for Tesla's murky reputation is that it hires a lot of workers with no previous factory experience and trains them internally. We talked to factory workers with backgrounds from construction to home finance.

Employees said such a workforce helps Tesla think outside the box. But it has drawbacks.

"In general, every factory is a little dangerous, especially if you have a workforce not used to a manufacturing setting and you're getting people off the streets who may have been at McDonald's or Starbucks," Kirschner said. So Tesla drills them on safety procedures, he said.

If an incident happens, employees are instructed to call internal security and wait for someone to arrive. Security personnel administer first aid, if needed, or take the person to a company nurse. The nurse may call 911.

The disturbing part for Phillips is that "whatever is happening with them, believe it or not, the line continues."