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Two of the industry's lamp giants have been making waves recently with a disagreement over how their low-mercury fluorescent products go about passing regulatory tests to qualify as non-hazardous waste.
The latest controversy concerns whether using chemical means-- specifically, ascorbic acid, or vitamin C--to render the mercury insoluble is an effective method for reducing mercury contamination when lamps are disposed of in a landfill.
GE Lighting, Nela Park, Ohio, last year introduced a line of fluorescent lamps under the "Ecolux" name. The line passed the Environmental Protection Agency's (EPA) toxicity characteristic leaching procedure (TCLP) to qualify as non-hazardous waste.
To reduce the amount of mercury leached by crushed lamps, GE Lighting's Ecolux line has a coating of ascorbic acid, which inhibits the solubility of mercury, in the lamps' end caps. In the TCLP test, entire lamps are crushed and steeped for 18 hours in a fluid mixture intended to simulate the sluice of chemicals commonly found in a landfill. Residue from the mixture is tested for mercury; the results determine whether the lamps pass the test.
Although the presence of ascorbic acid in the fluid mixture effectively neutralizes the threat of contamination, rival Philips Lighting contends that conditions in a landfill are unlikely to duplicate those in the laboratory--that, especially in longer lamps such as common 8-ft fluorescents, mercury is likely to never mix with ascorbic acid in the end caps.
GE Lighting stands by its design and the use of vitamin C for mercury containment. "The purpose of the ascorbic acid is to reduce the leachability of mercury," said Janice Fraser, manager--communications and government/media relations for GE Lighting. "It's simply a matter of taking different approaches to achieve the same objective. When we developed the Ecolux line, our scientists and engineers looked at a number of options that would achieve that same effect. Ascorbic acid proved to be effective and the most benign of the materials considered." Philips Lighting's Alto line uses no agents to neutralize the mercury, according to Steve Goldmacher, communications director for Philips Lighting.