LEBANON, LINN COUNTY, OREGON
In May 2002, the Oregon Department of Environmental Quality (DEQ) requested the assistance of the Oregon Department of Human Services (DHS) in determining whether complaints of peripheral neuropathy in a Linn County neighborhood were related to environmental exposure. The complaints focused on trichloroethylene (TCE) emitted by the ENTEK plant on Hansard Lane and the neurological symptoms experienced by nearby residents. TCE is used in a variety of industrial processes including degreasing operations, polyvinyl chloride production, adhesive formulation, and paints and coating. The Environmental Protection Agency (EPA) has classified TCE as a probable human carcinogen and TCE has been associated with a variety of non-cancerous adverse health outcomes, including neurological effects. DHS interviewed four complainants, reviewed existing environmental data, assessed the toxicological literature and reviewed the complainant's medical records. As a result of those efforts and limited air sampling data, DHS considers this site to be an indeterminate health hazard.
DHS received the original complaint from a resident living in the vicinity of ENTEK Manufacturing Inc., which is on Hansard Lane. The complainant became concerned with a link between air emissions and his symptoms after learning that two other Hansard Lane residents described similar symptoms of numbness and tingling in the extremities. In addition to ENTEK, a railroad, a seed company, and a gear and sprocket manufacturer are in the Hansard Lane vicinity1. Because of the known neurological effects of TCE , however, ENTEK became the focus of this health consultation—particularly because of the large scale of the ENTEK facility and its proximity to the households of concern. A review of the practices and chemicals used by the other businesses did not appear to be associated with the symptoms reported to DHS.
ENTEK Manufacturing, Inc. is a major extruder of plastic sheeting for use as battery separator material. After sheets are formed, residual oil must be removed by immersion in a solvent-in this case, TCE. If TCE escapes into the environment it would be as a vapor. Once in the air TCE will degrade into numerous byproducts, including dichloroacetyl chloride, formyl chloride and phosgene. The estimated half-life for TCE to degrade into such byproducts is 7 days. This indicates that TCE is not a persistent air contaminant . ENTEK has a permit to discharge TCE into the air, which discharges are monitored by the DEQ.
Because people spend more time inside their homes than in the workplace, exposure to airborne contaminants in the home is a matter of public health concern. Levels of organic compounds in indoor air can be two to five times higher than levels in outdoor air, depending on building materials and other products used within the home. A typical concentration of TCE levels in household air is 0.22 ppb .
ENTEK is located at 250 North Hansard Lane, in Lebanon, Oregon. The street is a mixture of residential homes and businesses. The original complainant lives on Hansard Lane, northeast of the ENTEK facility.
In 1988, ENTEK contracted CH2M Hill to conduct air sampling for TCE concentrations around the ENTEK property, as well as how fluctuating weather affects TCE levels. Air monitoring sample stations were established upwind and downwind of ENTEK property. Eighty-eight ambient air samples were recorded over 1 year. CH2M Hill monitored both stack and fugitive TCE emissions. Stack emissions refer to TCE exhausted from the system. Fugitive emissions are the difference between the total TCE purchased minus the amount of TCE that can be accounted for. Ambient air monitoring results are presented in Table 1.
|* ppbv = parts per billion by volume
For the fall sample season, stack samples were included with fugitive samples, since stack samples were on ENTEK property
Background ambient levels were measured upwind of the ENTEK facility
In addition to ambient air monitoring, ENTEK sampled the original complainant's household water supply well. No TCE or other solvents were detected in the well water. No air sampling has been conducted since 1988.
Citizen interviews and medical record evaluation.
Marilyn Scott (DHS) interviewed the complainants. Dr. Karen Southwick reviewed the medical records for each complainant. After careful evaluation of medical records and symptoms reported by those interviewed, no common pattern of peripheral neuropathy was determined among the four individuals. The complainants have a variety of medical conditions with known influences on numbness, pain, and tingling in the extremities.
The initial complaint came from a 53-year-old male with a history of exposure to multiple chemical agents, including Agent Orange and materials from pulp and paper mills. The patient was interviewed several times, including a recent interview on October 31, 2002. In 1991 the complainant had an injury to a disc between two cervical vertebrae, requiring neck surgery. He described tingling sensations in his hands, forearms and feet, increased clumsiness and falling, poor temperature sensation from the neck downward, and facial numbness. In the most recent interview the man stated his facial numbness occurs intermittently and that the peripheral neuropathy has moved towards his knees and elbows. To date, the man has not been given a diagnosis for his neurological problems.
In a nearby household, an elderly couple was interviewed about their health status. The couple has lived in their home for 12 years. The wife reports numbness in her hands, tingling in her feet, back pain, right knee pain, and right leg weakness. She has experienced chronic back and knee pain since 1998. Nerve conduction tests performed in July 2001 were normal. Some of these symptoms, however, appear compatible with a diagnosis of sciatica.
The husband reports that since 2001 he has experienced numb and swollen hands and numbness in his legs. He has chronic lower back discomfort, diabetes and osteoarthritis. He has been evaluated by a rheumatologist and given a possible diagnosis of rheumatoid arthritis. It should also be noted that diabetes commonly results in peripheral neuropathy, and arthritis can be associated with swollen extremities.
At the request of the original complainant, DHS contacted an employee of a nearby company. The employee does not live on Hansard Lane. The employee claimed that a single incident of chloropicrin exposure, possibly mixed with another unknown chemical, is the cause of their current symptoms, which include fatigue, depression, lack of bladder control, blue lips, tingling of the lips, tingling and numbness in the feet, migraines and sleep apnea. During chloropicrin applications the employee complained of cough, shortness of breath and nasal irritation. Although respiratory irritation is commonly associated with exposure to chloropicrin, the entire constellation of symptoms are not so linked. DHS was not given permission to review the employee's medical records.
Toxicology of TCE.
As stated, this health consultation focuses specifically on the neurological effects associated with inhalation of TCE. Typical neurological symptoms that could arise from inhaling TCE include headache, fatigue, drowsiness, decreased motor skills and depth perception . The Agency for Toxic Substances and Disease Registry (ATSDR) has derived an intermediate-duration inhalation minimum risk level (MRL) of 100 ppb, based on neurological effects in rats . This level is 10-fold greater than the highest level of TCE measured in ambient air in 1988.
Cranial and peripheral neuropathies have been associated with industrial and medical use of TCE, possibly arising from the effects of its breakdown products, including dichloroacetylene . In particular, the trigeminal nerve (one of the cranial nerves), which provides feeling and movement to part of the face, has been known to be affected. In one study, some evidence of trigeminal nerve impairment was seen in employees with long-term exposure to approximately 40,000 ppb of TCE. Symptoms such as facial numbness, jaw weakness, altered reflexes and facial discomfort have also been reported [6-7]. In a single patient case study, a retired metal degreaser who had been exposed to approximately 32,000 ppb of TCE for 20 years reported symptoms of fatigue, headache, vertigo, nausea, forgetfulness, and a loss of feeling in his hands and feet .
Many of the reports of adverse neurological effects and TCE exposure are derived from studies which examined the link between occupational exposure and relatively high concentrations of solvent. Typically, the levels of TCE found within a residence would be much lower than the levels measured at a commercial facility using TCE. One study examining the interaction between various factors on nervous system function and TCE exposure found that concentration, rather than exposure duration, was more important in determining adverse effects .
Given the lack of indoor air samples or current ambient air monitoring, DHS considers this site to be an indeterminate health hazard. There is no evidence that the complainants are currently being exposed to TCE through non-inhalation routes. Without air samples measuring TCE levels in their homes, it is impossible to determine whether any of these individuals are inhaling statistically significant levels of household TCE. Nevertheless, TCE levels measured from 1988 ambient air samples were much lower than levels associated with adverse effects in occupational settings.
A review of medical records did not find a consistent pattern of peripheral neuropathy among the persons interviewed. They have a variety of medical conditions that could influence numbness, pain and tingling sensations in their extremities. In addition, neuropathies most commonly attributed to TCE are associated with cranial nerves as opposed to peripheral nerves.
The individuals interviewed should continue to seek medical advice from appropriate specialists concerning peripheral neuropathy.
The collection of more air monitoring data, including monitoring of indoor air levels at the houses along Hansard Lane, would allow for better characterization of risk and exposure of individuals to TCE.
David Stone, Ph.D.
Public Health Toxicologist
Environmental Services and Consultation
Oregon Department of Human Services
Karen Southwick, M.D.
Environmental and Occupational Epidemiology Section
Oregon Department of Human Services
Marilyn Scott, CSP, ARM
Environmental and Occupational Epidemiology Section
Oregon Department of Human Services
. US Environmental Protection Agency. Integrated Risk Information System (IRIS). Washington, DC; August 14, 2002. URL: http://www.epa.gov/IRIS/subst/index.html.
. Agency for Toxic Substances and Disease Registry. Toxicological profile for trichloroethylene (update). Atlanta: US Department of Human Services; 1997.
. Bardana EJ. and Montanaro A. In: Dekker M, Ed. Indoor air pollution and health. New York: Inc; 1997.
. Arito H et al. Effect of subchronic inhalation exposure to low-level trichloroethylene on heart rate and wakefulness-sleep in freely moving rats. Sangyo Igaku 1994;36:1-8.
. Ellenhorn MJ and Barceloux DG. Medical toxicology-diagnosis and treatment of human poisoning. New York: Elsevier Science Publishing Co., Inc.; 1988.
. Buxton PH and Hayward M. Polyneuritis cranials associated with industrial trichloroethylene poisoning. J Neurol Neurosurg Psychiatry 1967;30: 511-18.
. Feldman RG. Facial nerve latency studies in man-effects of trichloroethylene exposure. Electromyography 1970;10:93-100, .
. Kohlmuller D and Kochen W. Exhalation air analyzed in long-term post-exposure investigations of acetonitrile and trichloroethylene exposures in two subjects. Clin Chem 1994;40:1462-64.
. Bushnell PJ. Concentration-time relationships for the effects of inhaled trichloroethylene on signal detection behavior in rats. Fund Applied Toxicol 1997;36:30-38.
This Hansard Lane Public Health Consultation was prepared by the Oregon Department of Human Services under cooperative agreement with the Agency for Toxic Substances and Disease Registry. It is in accordance with the approved methodology and the procedures existing at the time the public health consultation was begun.
Technical Project Officer, SPS, SSAB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health consultation and concurs with the findings.
Lisa C. Hayes
for Chief, State Program Section, DHAC, ATSDR
1 This information is based on observations by the authors.