This is the last part of the lists of Radioactive Consumer Products, but this does not mean that only the featured items here are radioactive. There are some other items that I have not yet stumbled into. Rest assured that if I found something new, I will immediately post it here.

The thorium-containing incandescent mantle was invented in 1884 by Carl Auer von Welsbach, an Austrian chemist, and it is sometimes referred to as a ?Welsbach mantle? or ?Auerlicht.? This invention resulted in the first commercial use of the element thorium. Today, these mantles are generally used in portable lanterns for camping. Some are used in outdoor light fixtures, and some are used indoors, especially in vacation cabins.

The mantles are produced by dipping a meshed fabric (e.g., nylon web) into a solution of thorium nitrate. Other metals are added to the solution for a variety of reasons. For example, cerium is added to increase the light output, while beryllium increases the mantle?s strength. The fabric is then removed from the solution and dried. Lastly, it is coated with lacquer and fashioned into one of two types of mantles: a soft mantle or a hard mantle. The soft mantle is essentially a bag with either a drawstring or some type of fitting that attaches the mantle to the burner. The fabric of a hard mantle is supported by a metal frame that gives it a dome-like shape.

In use, a jet of combustible gas is blown through the mantle. When the gas is lit, the mantle heats up and the thorium emits an incandescent glow. The temperature must be 2000 degrees centigrade or so for this to occur. When the mantle is heated up for the first time (a cure), the thorium is converted to thorium oxide, the lacquer is burned off, and a variety of materials are released into the air. The material becoming airborne includes approximately 50 % of the beryllium and many of the radioactive decay products of the thorium.

Thoriated welding rods are used as electrodes in tungsten inert gas (TIG) welding in which the rod serves as a "nonconsumable" electrode. The rod is actually consumed during use, but it does not act as a filler that binds two pieces of metal together. The rate of consumption is approximately 0.1 to 0.3 mg/minute for typical currents but it can be as high as 50 to 60 milligrams per minutes for the maximum rated currents. This consumption probably involves volatilization and the loss of tiny droplets at the electrode tip. Because TIG welding is expensive, its is limited to those situations that require high quality results (e.g., the aircraft and petrochemical industries).

By weight, the rods are usually 1 or 2 % thorium oxide (thoria) although higher concentrations, up to 4 %, have been used. The rods are color coded to indicate the thoria content: yellow indicates 1 %, and red indicates 2 %. The color usually appears as a band at one end of the rod (like that in the photo to the right). While they range from 0.25 to 6.35 mm in diameter and 7.6 to 61 cm long, a ?typical? rod would be about 2.4 mm in diameter, 15 cm long, and contain 0.23 grams of thorium. Estimates over the last two decades put the annual production at 1 to 5 million electrodes.

Thorium is added to the tungsten because it increases the current carrying capacity of the electrode and it reduces contamination of the weld. In addition, it is easier to start the arc and the latter is more stable.

Some of the old cats eye marbles, possibly other types as well, owed their yellow color to uranium. Note that the activity of the uranium is far too low to be detectable with a simple survey meter.

Vaseline glass, like the candlestick holder shown here, is a term for the transparent yellow to yellow-green glass that owes its color to its uranium content. Purists might argue that the green sugar bowl in the picture should not be considered Vaseline glass because an additional colorant (probably iron) has been used in addition to the uranium to produce the green. These cognoscenti might describe it as ?Depression Glass,? a less desirable commodity.

Vaseline glass is a recent term that probably dates from the 1950s. Uranium glass, an older and more general term, is sometimes used as a synonym for Vaseline glass, but this can lead to confusion because some types of glass colored with uranium (e.g., custard glass and Burmese glass) are opaque whereas Vaseline glass is transparent. Canary glass is an even older name that was first used in the 1840s to describe what is now referred to as Vaseline glass.

New York State Department of Health issued a press release warning that some pieces of yellow-orange and off-white (beige) cloisonn� jewelry were radioactive. While it did not consider the jewelry a hazard, the state recommended that the public discard it or return it to the place of purchase. After the press release was reported, the matter was taken under consideration by the Nuclear Regulatory Commission. One early course of action taken by the NRC was to contact officials in Taiwan and request that the Taiwanese exporters cease the distribution of cloisonn�.