Work on the vast expansion of the Metro Purple Line in Los Angeles has come to an abrupt stop following dozens of worker injuries and safety concerns that officials say have not been addressed.

“Metro has ordered its contractor to temporarily suspend all field work on the Purple Line Extension Section 2 Project due to the unacceptable rate of serious worker injuries,” Metro said in a statement Tuesday. “Safety is and will always be our first priority. The safety of those building our county’s transportation projects must always be protected.”

In a letter to Tutor Perini, the general contractor, Metro mentions nine recorded injuries over the past twelve months, including five in the last three months, and “many more incidents that could have been more serious.”

The suspension of work began on Oct. 21.

Metro is demanding Tutor Perini take several steps, including a “comprehensive root cause evaluation” of the injuries, and has ordered to contractor to draft a revised safety plan before work on the Purple Line can resume.

“We expect the contractor to improve its safety policies and to demonstrate its full compliance with all of Metro’s contract safety requirements before we allow work to continue,” the letter reads.

In a statement to KTLA, Tutor Perini said, “safety is of utmost importance on all our jobsites. We are firmly committed to providing a safe and healthy work environment for our employees and to working in a manner that ensures the safety of our subcontractors, customers and the general public, as well as the protection of facilities, equipment and the environment.”

The Purple Line Extension project will add seven new stations connecting L.A.’s Westside to downtown.