## 1 Introduction  
Humans are continually exposed to ionizing radiation, most pointedly from the natural radionuclides within terrestrial media. The ubiquitous nature of naturally occurring radioactive material (NORM) is well understood, with a presence in soil, water, and air. Less well appreciated is that NORM also appears in consumer products, including in building materials [1]. While exposure to ionizing radiation emitted by \({}^{238}\)U, \({}^{232}\)Th, and \({}^{40}\)K can constitute a risk to the living environment [2,3], the low doses from most natural environments do not typically give cause for concern. However, certain anthropogenic activities can increase radioactivity concentration levels, with elevated doses sometime well beyond those of the natural background [4]. For individuals who are exposed at these levels, NORM contributions may cause cancer [5]. Accordingly, from the viewpoint of radiation protection, the monitoring of natural radioactivity in human surroundings is of primary importance. In Malaysia, the country in which present study was conducted, a recent health fad concerns online undergarment products markets, and the present study addresses the NORM content of these so-called negative ion garments. Negative ion technology has been suggested to offer alternative medical benefits [6]. At the outset, let it be noted that the term 'negative ion' finds no conventional scientific definition, and is considered by the present authors to be meaningless jargon. The manufacturers of these undergarments state them to be composed of touralnine or minerals; the purveyors and manufacturers linking the supposed health benefits with negative ion technology, using further jargon such as \"negative ion waist shaper\". The claimed health benefits include enhanced magnetic therapy, improved cardiovascular function, blood circulation, immune system function, and also the burning of excess fats and calories, together with a boosting of metabolism, the removal of bodily toxins, and assistance in material detoxification [5; 6]. Additional claims include that they are a way to maintain a balance in energy and improved emotional well-being, as well as protecting against electromagnetic fields [7]. Despite NORM-added consumer products being readily available in the market, little is known about their effects in terms of dose exposure and any potential hazard to health, and they are fully unmonitored. In the only other related study that we have been able to find in the literature, it was reported that an inhalation risk can exist in the case of misuse of NORM-added toiletry products, available in the Japanese and Korean markets [5; 8; 9; 10]. Given that, over time, risks have been identified, NORM has become increasingly subject to monitoring and regulation [9]. In particular, while the IAEA safety guide \"Radiation Safety for Consumer Products\" [11] recommends that the use of such items first be justified, negative ion garments are being sold on the open market with no supportable scientific evidence being proffered in terms of benefits to the general public from the added radioactive component [11; 12]. Among notable particular actions are that of the United States Environmental Protection Agency (EPA) via its guidelines for regulation of NORM [13]. Despite such isolated actions, globally harmonized regulations remain to be established, regulating and controlling radioactive content consumer products [14]. A further isolated action in seeking to limit radiation exposure from NORM-added consumer products is that of the Malaysian Atomic Energy Licensing Board (AELB), seeking control of such items via its technical document LEM/TEK/69 [15]. The intent of present study is to investigate negative ion undergarments, the activity of the long-lived radionuclides \({}^{238}\)U, \({}^{232}\)Th and \({}^{40}\)K being measured along with potential dose to wearers, the latter evaluated via use of Geant4 Monte Carlo (GMC) simulation.