GUILFORD COUNTY, N.C. — Detectives seized more than 5,000 THC oil vape cartridges Thursday as recent vaping-related illnesses, in some cases involving THC, gain national attention, according to the Guilford County Sheriff’s Office.

At about 5 p.m., Guilford County detectives found about 5,058 “Cookies”-branded cartridges that were headed to Richmond, Virginia.

The cartridges contained about 1 ml of 91% THC oil marketed as “Lemon Pound Cake” flavor.

The sheriff’s office says the cartridges are made to be placed in an e-cigarette or similar device.

The sheriff’s office estimates the cartridges are worth about $250,000.

No one was arrested as detectives continue investigating.

THC oil cartridges such of these have risen to national notoriety after multiple vaping-related illnesses, which, in some but not all cases, involved THC.

Vaping-related illnesses have been linked to eight previous deaths — two in California and one each in Kansas, Illinois, Indiana, Minnesota and Oregon. CDC health officials said on Thursday they expect more deaths to be reported. It is unclear exactly how many of these may be related to THC oil cartridges.

The CDC and various state health departments have reported widespread use of products containing THC, or tetrahydrocannabinol, the psychoactive substance within cannabis, among people who became ill. But health officials emphasized that not all people who became ill had used THC, and many had used multiple substances.

Still, health officials said they haven’t found a definitive cause or a clear connection between cases, and they warned that patients worried about becoming ill from vaping should refrain from using e-cigarettes.

Adults using e-cigarettes to quit smoking should not return to cigarettes, CDC officials said, but instead should talk to a health care provider about other tools to help them quit.

If people who vape experience symptoms, they should seek medical care.