Ford and Jesse Ireland, lottery specialists, volunteered to be the two of six commission employees to keep vigil until the 180-day deadline to claim the jackpot that expired at midnight. They said they volunteered because overtime is "hard to come by," especially within a state agency.

"The best I can say is, you know, I don't have a family, he doesn't have a family, so I don't have to be anywhere until late," Ireland said. "No obligations. No children."

This jackpot was the fourth to go unclaimed in the 11-year history of Lotto Texas, said Kristina Tirloni, spokeswoman for the Texas Lottery Commission and another of the six employees who waited for the deadline to pass. The largest unclaimed jackpot was worth $13 million.

"It happens once in a blue moon," Ford said.

Tirloni said there have been 476 tickets sold since the inception of Lotto Texas that have matched all six numbers in the drawing.

The last time the jackpot went unclaimed, Tirloni said the office received a call from a man in Dallas who said he had the winning ticket and was on his way to Austin.

"We said, 'Well you're going to have to drive very fast,'" Tirloni said, adding that the man never showed up at the claims department.

Jackpot winners have to bring the ticket in person to the claims department before midnight in order to receive the prize, said Reagan Greer, executive director of the commission.

Once a ticket is brought in, Ford said the 18-digit number on the back of the ticket must be run through their system to validate it, a process that takes only a few minutes.

Jackpot winners must fill out a claim form and show valid identification before the ticket can be verified. So Ford said the winner would have to arrive with enough time to fill out the single-page form.

The unclaimed money for this jackpot will be transferred into the Tertiary Care Medical Program, which compensates state trauma centers for unreimbursed indigent health care, said Peggy Belcher, spokeswoman for the Texas Department of Health.

The UT Medical Branch received its limit of $40 million in unclaimed lottery prize money during the last biennium, which ends Aug. 31, Belcher said. Because of changes in the appropriations bill during the last regular legislative session, UTMB will only receive $20 million for the upcoming biennium, which begins Sept. 1.

The winning Lotto Texas ticket, purchased at a Diamond Shamrock gas station in San Antonio, was worth a little more than $3 million because the winner selected the "cash value option."

Under this option, the winner receives a one-time lump sum equivalent to the "net present value" of the jackpot, which is generally about half of the value of the jackpot, Tirloni said.

The jackpot for tonight's drawing is $47 million, currently the largest jackpot in the nation, Greer said.