Two people whose bodies were removed from the cruise ship Summit after it docked at Honolulu Harbor yesterday morning appear to have died from natural causes in unrelated incidents, a spokesman for Celebrity Cruises said.

Michael Sheehan, a spokesman for the Miami-based Celebrity, said an 83-year-old man, who was a U.S. citizen, suffered an apparent heart attack and died while the ship was at sea.

In addition, a 40-year-old woman who had "cancer issues" also died at sea while the ship was en route to Hawai'i from San Diego, Sheehan said.

Both passengers died Sunday.

Two other men aboard the Summit were referred to local medical facilities after it docked at Pier 10 at Aloha Tower, Sheehan said.

One of the men, 69, reported numbness in his hands and feet, which was acute and progressive. The other man, 76, may have had a mini-stroke.

The two fatalities are not expected to interfere with the schedule of the Bahamian-flagged Summit, Sheehan said.

It left San Diego on Friday with a crew of 936 and 1,977 passengers.

The Summit was scheduled to depart Honolulu for Lahaina, Maui, last night, arrive in Hilo on Saturday and sail on to Kailua, Kona, on Sunday. It is scheduled to depart for San Diego later Sunday and arrive back on the West Coast Nov. 9.

Scott Ishikawa, spokesman for the state Department of Transportation, called the deaths "an unfortunate coincidence."

"Trips on cruise ships often appeal to the elderly, which was the case in one of the deaths," Ishikawa said.

"We understand that the second person who died was battling cancer, so it appears both deaths were due to natural causes and there were no suspicious circumstances," he said.

He said the bodies were turned over to the Honolulu medical examiner for autopsies if deemed necessary.

Janice Okubo, spokeswoman for the state Department of Health, said deaths or sickness aboard cruise ships must be reported to the U.S. Centers for Disease Control and Prevention if they involve contagious infections or diseases.

Both deaths aboard the Summit appear to have been the result of natural causes, so the cruise line would not have been required to contact the center, Okubo said.

"We have a medical facility on board that would obviously assist anyone who is in ill health," Celebrity Cruises' Sheehan said. "If you have an unfortunate situation where someone passes away, we have a guest care team that specifically assists the families and the people on board who may be traveling with the (deceased) person as well as the family on the shore side."

A death aboard the ship is reported to local authorities at the next port of call, Sheehan said.

The Summit's inaugural voyage was in October 2001. The 965-foot ship has a capacity of 2,034 passengers.

In August 2006, the Summit pulled into Seward, Alaska, with a nearly 30-foot long dead humpback whale pinned to its bow.

Humpbacks are endangered species but federal officials investigating the incident said at the time that the crew did not appear to do anything wrong.

The Summit apparently hit the whale sometime after leaving Disenchantment Bay near Yakutat. The whale was spotted by longshoremen at the Seward dock.

Reach David Waite at dwaite@honoluluadvertiser.com and Dan Nakaso at dnakaso@honoluluadvertiser.com.