CRANSTON — Two underground electrical fires Sunday night temporarily knocked out power to the Eleanor Slater Hospital and six state departments at the Pastore Campus, disrupting telephone and Internet service and cutting off air conditioning yesterday, one of the hottest days so far this year.

Although backup generators quickly kicked in, phone lines were still down late yesterday in many of the government buildings, and the central air conditioning in two hospital buildings that house patients was not restored until last night.

No one was hurt by the fires or the resulting power interruption. The backup generators kept essential services running, including the ventilators of the 19 patients in the state hospital who cannot breathe on their own.

However, six state departments with offices at the complex suffered disruption. The departments are: Children, Youth and Families; Corrections; Elderly Affairs; Human Services; Labor and Training; and Mental Health, Retardation and Hospitals.

In addition, phone service to the main Department of Motor Vehicles office in Pawtucket was not working all day. The DMV’s operator control office is located on the Pastore Campus. The DMV’s computer service and phone service in its branch offices, however, were not affected.

Most of the problems from the power failure at the Pastore Campus were addressed quickly, without causing serious complications. For example, the Adult Correctional Institutions lost outside phone lines, but a Department of Corrections spokesman said internal communication was unaffected.

Also, the offices of the Department of Labor and Training went without phone and Internet service until late yesterday afternoon. Despite the interruption, approximately 8,000 people still received their unemployment insurance, which they would regularly get through a direct-deposit system. Because the phone lines weren’t working, information was transferred to a secure disk, which was then taken to an off-site location from where it could be transmitted, according to a department spokeswoman.

The Eleanor Slater Hospital, with nine buildings at the complex and 225 patients, had the greatest problems. Without air conditioning in the buildings, temperatures in parts of the hospital climbed to 79 degrees. Lights were dimmed throughout the hospital to conserve energy.

Two large generators were brought in yesterday afternoon, and power was fully restored at the hospital’s two main buildings by late last night.

The fires started around 9:15 p.m. Sunday in electrical distribution wires that run underneath the Pastore Complex. A night supervisor smelled smoke and called the Cranston Fire Department, according to Ellen R. Nelson, director of the state Department of Mental Health, Retardation and Hospitals.

“Basically, the circuits overloaded,” she said.

Kevin Richard, chief of electrical generation and distribution at the complex, said the fires were caused by deteriorating power lines that date back 30 years. He said the fires were unconnected, with the timing just a coincidence.

The Pastore complex has its own power plant but is also connected to outside power. At the time of the fire, about 50 percent of the campus’ power was coming from National Grid.

A National Grid spokesman said yesterday that the damage was unrelated to the electrical feed the company provides to the complex. No homes or businesses outside the complex lost power because of the fires.

Backup generators, powered by diesel, were in operation all night Sunday and most of yesterday. Although they were refueled yesterday, they’re not designed to run for long periods, according to Bill Anderson, deputy chief of the Pastore Campus.

As part of the complex’s emergency response plan, the large generators were trucked in from Southworth Milton, of Milton, Mass., and taken to the hospital, which had the greatest need, Anderson said.

The Rhode Island Department of Emergency Management also supplied two smaller generators to the hospital. They remained there late yesterday in case of another disruption. The Cranston Fire Department also brought in large reels of extension cords that could be used to connect to a power source outside the complex.

Dr. David R. Gifford, director of the state Health Department, said his department sent inspectors to the hospital yesterday morning to make sure patients were safe, and they found nothing amiss.

“The patients on ventilators and other patients — nothing adverse happened to them,” Gifford said. “Care has proceeded.”

The biggest challenge now, he said, is planning to cope over the next few days while the damage is assessed and repaired.

Nelson said that no patients had been transferred out of the hospital. The 19 patients on ventilators were being monitored. Battery packs that can power a ventilator for about three hours were delivered to each patient’s room in case of further problems.

“We’re being very cautious,” she said.

Emergency phone lines at the hospital were also opened yesterday afternoon. People seeking information about patients should call 255-0910; those with inquiries about staffing at the hospital should call 255-0904. For all other business, call 255-0912.

Visiting hours remain the same: noon to 8 p.m.

Technicians were working last night to reconnect phone lines throughout the Pastore Campus. A news release from the state Department of Administration said the lines could be up by today. But, according to the release, it could be three to four days before the power lines destroyed by the fires are replaced and the electrical distribution system at the complex is back to normal operation.

Although the complex’s power plant was not damaged, there is no way to get power from the plant to the buildings until the underground damage is repaired.

With staff reports from Mark Arsenault and Karen Lee Ziner.

ffreyer@projo.com