Roughly 4,000 nurses at Brigham and Women’s Hospital in Boston walked to the picket line early Wednesday morning in what the union says is the largest nurses strike in Massachusetts history.

Nurses at the state’s second-largest hospital had planned a one-day strike starting at 7 a.m. on July 8, according to the Massachusetts Nurses Association. But the union says that hospital management plans to keep striking nurses off the job for five additional days.

Nicolette Dickerhoff, a neonatal nurse practitioner at Brigham and Women’s Hospital, said Mass General Brigham has consistently not offered to increase their wages. (MGB told GBH News Monday that it gave nurses an across-the-board 3% wage increase in October)

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“They don’t believe in giving us a fair contract to take care of these people that literally come from all over the world, and we’re not going to tolerate it,” she said. “Safe nursing, safe ratios save lives, and that is what we’re here for today.”

The strike follows seven months of labor negotiations between the MNA and Mass General Brigham, which operates the hospital. Both sides have been stuck on wages, healthcare contributions and more investment in permanent staff instead of temporary travel nurses.

Separate from the nurse strike, roughly 450 Mass General Brigham home care clinicians also walked off the job on Wednesday with their negotiations also stuck on pay.

Gov. Maura Healey even stepped in to try to prevent the strike, meeting Monday afternoon with leaders from the union and Mass General Brigham. But no members from either bargaining committee participated in the meeting, according to State House News Service.

Mass General Brigham is not offering a wage increase, the MNA said, and is asking nurses enrolled in the Harvard Pilgrim Health Plan — roughly half of the union’s members — to pay 2.5 percentage points more of their monthly premium.

“Most of us are living paycheck to paycheck because of how expensive Boston and Massachusetts in general is,” Dickerhoff said. “In addition to that, the hospital wants to increase the premiums on our health insurance, and I mean, that essentially equates to a pay cut for us.”

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Megan Ostrowski, a medical ICU nurse at Brigham and Women’s Hospital, calls the proposed zero percent increase “disrespectful.”

“You see what they’re willing to pay the scab nurses to come in who aren’t qualified. They’re not trained in our hospital policies,” said Ostrowski, who is also on the MNA’s Board of Directors. “They do like a couple days of training and the hospital says that they’re going to provide competent care, but you absolutely can’t provide the same level of care with such little experience.”

The hospital said patient care won’t be affected and that it has hired nearly 1,300 replacement nurses to cover shifts throughout the strike. But nurses said this still puts adequate patient care at risk.

“There are 4,500 of us nurses on strike. They only brought in 1,300 nurses to cover us,” Dickerhoff said. “That’s not even a third. That’s not high-level care. That’s the opposite.”

MGB told GBH News on Monday that fewer replacement nurses were hired because they will each work five days.

Tarcia Edmunds-Jehu, a nurse midwife at Brigham and Women’s Hospital, said that the supports they’re asking for would help improve nurse retention.

“At a facility like this, we need to have those nurses to take care of the really medically complex patients that we take care of here,” she said. “If you don’t support the nurses, you’re not supporting the patients.”

A Mass General Brigham spokesperson previously told GBH News that nurses would be off the job for more than one day because “...Mass General Brigham must make extensive emergency preparedness arrangements to ensure continuity of patient care.”

The nurses strike and lockout is expected to end at 7 a.m. on July 13.

The strike of 450 home care clinicians is expected to last seven days, ending on Wednesday, July 15, according to the MNA.