After three patients died while under the trust's care, it will be prosecuted.
Charges are being brought against the Tees, Esk and Wear Valleys (TEWV) NHS Trust by the Care Quality Commission (CQC).
It is understood that Christie Harnett, 17, Emily Moore, 18, and a third person are all charged with the offense.
Insufficient "safe care and treatment" was allegedly provided by the trust, placing patients at "significant risk of avoidable harm.".
Both young women had previously received care at the Middlesbrough hospital West Lane, which was shut down by inspectors in 2019 as a result of serious concerns.
In 2019, Newton Aycliffe resident Miss Harnett passed away in the hospital.
In 2020, Miss Moore of Shildon passed away at Durham's Lanchester Road Hospital after committing suicide.
The identity of the third party is unknown.
A total of 120 failures were discovered in the "care and service delivery" across a number of agencies last year, according to independent reports NHS England had commissioned.
The CQC, which oversees health and social care services in England, announced in June of last year that it would be bringing legal action against the trust for failing to safeguard Miss Harnett.
At the time, it said the circumstances surrounding the death meant the CQC had looked "at all the evidence to determine if it meets the threshold for the CQC to prosecute the provider".
Furthermore, "in this instance, it was determined that the evidence did meet the standard, making a prosecution both necessary and in the public interest. ".
The CQC announced on Friday that it was now bringing legal action against the trust over the deaths of two more people.
All of the patients involved, according to a CQC spokesperson, had been under the trust's care.
David Moore, Miss Moore's father, revealed to the BBC that some of the alleged offenses involved his daughter's care.
The Health and Social Care Act, which deals with healthcare providers' obligations to "ensure people receive safe care and treatment," was "breached" by the trust, according to the CQC.
An official from the trust responded by saying, "We have fully cooperated with the Care Quality Commission's investigation and continue to work closely with them.
"We have made significant progress in the past two years and continue to be committed to providing our patients with safe and compassionate care. ".
The first hearing is scheduled to occur at Teesside Magistrates' Court on May 17.