This reminds me of the aphorism "Programming today is a race between software engineers
striving to build bigger and better idiot-proof programs, and the Universe trying to
produce bigger and better idiots. So far, the Universe is winning."
The same might be said for hardware engineers. I guess there is just no way to design
and make an idiot-proof product.
Chuck Dolci
James, Chris wrote:
> In December 1991, a venous blood lead level (BLL) of 50 ug/dL
> was detected in a 46-year-old Ohio man during a routine pre-employment
> examination. He was referred to a university-based pharmacology and
> toxicology clinic for further evaluation; clinic physicians investigated
> the case. Although a repeat BLL obtained 1 month later was 51 ug/dL, he
> reported no exposure to known sources of lead during the interim.
> However, he reported numbness of his fingers and palms, tinnitus, and a
> possible decrease in his ability to perform basic arithmetical
> calculations.
> A comprehensive occupational and environmental history obtained
> at the time of the second BLL test revealed no apparent source of his
> lead exposure. Although he had been employed for approximately 20 years
> as a microwave technician during military service and while employed at
> a television station, he reported no history of exposure to lead from
> soldering or welding. He had no activities or hobbies associated with
> exposure to lead or lead products, no previous bullet or birdshot
> wounds, and he denied drinking illicitly distilled alcohol or using lead
> additives in his car.
> His residence was built in 1974 (after lead was banned from use
> in residential paint) *, and household water was obtained from a well.
> In January 1992, blood lead testing of family members revealed levels of
> 5 ug/dL for his wife and less than 5 ug/dL for his 17-year-old child.
> His only medication was ranitidine **, which he had used for the
> previous 1-1/2 years for "indigestion." He reported occasional cigarette
> smoking.
> Although results of a neurologic examination were normal,
> neuropsychiatric testing on March 13 demonstrated mild memory deficits,
> as evidenced by abnormalities on verbal and figural memory tests.
> Because of these abnormalities, beginning March 13, he was treated for
> 19 days with dimercaptosuccinic acid (DMSA), an oral chelating agent,
> and on April 4, his BLL had decreased to 13 ug/dL. However, BLLs on May
> 15 and July 23 were 49 ug/dL and 56 ug/dL, respectively.
> During a July 1992 follow-up clinic visit, he mentioned that for
> approximately 20 years he had habitually chewed on the plastic
> insulation that he stripped off the ends of electrical wires. Samples of
> the copper wire with white, blue, and yellow plastic insulation were
> obtained and analyzed for lead content. The clear plastic outer coating
> (present on all colors of wire) and the copper wire contained no lead;
> however, the colored coatings contained 10,000-39,000 ug of lead per
> gram of coating. *** On receipt of these results, he was instructed
> immediately to discontinue chewing the wire coating.
> In January 1993, when his BLL was 24 ug/dL, he reported
> subjective improvement in his symptoms; follow-up neuropsychiatric
> testing is pending.
> Reported by: M Kelley, MD, P Walson, MD, D Thorton, PhD, Ohio
> State Univ and Children's Hospital, TJ Halpin, MD, State Epidemiologist,
> Ohio Dept of Health. Div of Surveillance, Hazard Evaluations, and Field
> Studies, National Institute for Occupational Safety and Health, CDC.
> Editorial Note
> Editorial Note: This report likely represents the first
> documented case of lead poisoning following ingestion of lead as a
> consequence of chewing on plastic wire coatings. Plastic coatings
> previously have been associated with lead exposure in the burning of
> lead-containing plastics during repair of a storage tank (1), the
> production of plastics (2,3), and the manufacture and use of stabilizers
> and pigments in the plastics industry (4). Although lead exposure also
> can occur among workers who burn the plastic coating off copper wire to
> recycle the copper, lead intoxication by this route has not been
> reported (5).
> Lead compounds may be employed in the production of colored
> plastics (in which lead chromates are used as pigment) and in the
> manufacture of polyvinyl chloride (PVC) plastics (in which 2%-5% lead
> salts {including lead oxides, phthalate, sulfate, or carbonate,
> depending on the desired quality of the final product} are used as
> stabilizers). Although environmental regulation has reduced considerably
> the amount of lead used in the United States in the manufacture of PVC
> plastics, manufacturers of electrical wire and cable continue to produce
> PVC stabilized and/or pigmented with lead compounds (6).
> More than 573,400 U.S. workers are employed in occupations
> involving electrical work. Among these workers, potential for excessive
> exposure to lead may result from inhalation of fumes generated during
> lead soldering (7). Because the plastic coating from wires is usually
> removed by mechanical stripping, ingestion of lead from these plastic
> coatings is probably uncommon. Nonetheless, the findings in this report
> remind occupational and other health-care providers of the need to be
> aware of this potential source of lead exposure. In addition, workers
> should be warned of the potential hazard of chewing plastic coatings or
> other plastic products that may contain lead.
> References
> 1. Skillern CP. Experience with burned lead-in-plastic material. Am
> Ind Hyg Assoc J 1969;30:648-9.
> 2. CDC. Lead chromate exposures and elevated blood lead levels in
> workers in the plastics pigmenting industry -- Texas, 1990. MMWR
> 1992;41:304-6.
> 3. Ong CH, Ong HY, Khoo NY. Lead exposure in PVC stabilizer
> production. Appl Ind Hyg 1989;4:39-44.
> 4. CDC. Surveillance of elevated blood lead levels among adults --
> United States, 1992. MMWR 1992;41:285-8.
> 5. Liss GM, Halperin WE, Landrigan PJ. Occupational asthma in a
> home pieceworker. J Occup Med 1986;41:359-62.
> 6. The Vinyl Institute. Characterization of lead in plastics
> products in municipal solid waste, 1970 to 2000. Prairie Village,
> Kansas: Franklin Associates, Ltd, 1990.
> 7. NIOSH. Health hazard evaluation report no. HETA 90-075-2298.
> Cincinnati: US Department of Health and Human Services, Public Health
> Service, CDC, 1993.
> * 16 CFR section 1303.2. Ban of lead-containing paint and
> certain consumer products bearing lead-containing paint.
> ** Ranitidine alters gastric acidity, which theoretically can
> influence gastrointestinal absorption of lead.
> *** Samples were analyzed using graphite furnace atomic
> absorption spectroscopy, following dissolution of the plastic coating in
> tetrahydrofuran.
>
>
>
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