Rep. Ralph Norman holds a narrow lead in South Carolina's crowded Republican Senate primary to replace the late Sen. Lindsey Graham, but no candidate has emerged as a clear frontrunner, according to a new poll released Thursday.

According to an Emerson College Polling/Nexstar Media poll, Norman led with 16.4% support, followed by businessman and ordained deacon Mark Lynch at 12.5%, reports The Hill. 

Rep. Nancy Mace received 10.1%, Lt. Gov. Pamela Evette had 9.9%, Rep. Russell Fry drew 9.4%, Gov. Henry McMaster earned 7.7%, and former Gov. Mark Sanford received 5.4%.

Overall, the survey found 17.9% of likely Republican primary voters remain undecided, the largest single share of respondents.

The Emerson College Polling/Nexstar Media survey was conducted July 14-15 among 500 likely Republican primary voters in the state and carried a margin of error of plus or minus 4.3 percentage points.

South Carolina voters will choose the GOP nominee in a special primary on Aug. 11. If no candidate wins a majority of the vote, the top two finishers will advance to an Aug. 25 runoff.

The winner will appear on the November general election ballot to serve the remainder of Graham's term.

Sen. Darline Graham Nordone, who was appointed Monday by McMaster to fill the seat vacated by her late brother, garnered 5.9% support.

Graham, who died Saturday night after suffering an aortic dissection, was seeking a fifth Senate term at the time of his death.

No candidate reached 20% support in the survey, underscoring the wide-open nature of the race ahead of next month's Republican primary.