Oskaloosa ? A measuring device taken in a recent farm burglary contains a small amount of radioactive material and could injure someone if exposed to it for a long period of time, Jefferson County Sheriff’s officers and state officials said.

The device, a nuclear density gauge, was among items taken from a barn and a residence in the area of 126th and Rawlins Road between Oskaloosa and Winchester. The burglary was reported Sunday.

The gauge is used to measure the density of concrete or asphalt. It is registered with the Kansas Department of Health and Environment because of the radioactive material. A $500 reward is being offered for the return of the gauge by McAfee, Henderson and Strick Inc.

If someone were to get to the radioactive material and carry it around with them for a long time or had some long-term exposure to it, it could be harmful, KDHE spokeswoman Sharon Watson said.

The gauge is a Troxler model 3440, serial number 31113 (See instruction manual). It is in a yellow rectangular storage case, about 32 inches long by 17 inches wide and 18 inches tall. The case has a radioactive yellow II label on the side.

Sheriff’s officers originally believed early today the device contained plutonium. However, Watson said this afternoon that was not the case.

Anyone with information about the burglary or the whereabouts of the gauge or other stolen items is asked to call the sheriff’s office at 785-863-2765, or the communications center at 785-863-2231.