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Health of Pathology Laboratory Technicians at Risk from Common Solvents like Xylene and Toluene

Study identifies increased incidence of Raynaud’s phenomenon among pathology laboratory staff who work with certain chemicals

Pathologists responsible for health and safety in histology and cytology laboratories will be interested in the results of a newly published study involving staff exposure to certain chemicals. Researchers determined that medical laboratory technicians who handle common solvents develop auto-immune connective tissue diseases in increased numbers.

The new study was published this month in the Journal of Rheumatology. It offers credible evidence that clinical laboratory technicians, pathologists, and scientists who work with toluene and xylene double their chances of developing a vascular condition known as Raynaud’s phenomenon (RP). And for those who work with toluene and xylene combined with acetone or chlorinated solvents, the chance of developing severe RP increases by a factor of nine!

Majority of Cases Involve Women Who Work in Pathology Laboratories

The study was conducted at the University of Otago, in Wellington, New Zealand. Researchers asked all the histology laboratories and cytology laboratories in New Zealand to participate in the study. Every laboratory department in the nation agreed and provided data and access to laboratory workers.

A total of 341 medical laboratory technicians participated in the study, most of whom were women (79%). Those who came into contact with toluene and xylene on a regular basis were twice as likely to develop Raynaud’s phenomenon. However, those who worked with acetone or chlorinated solvents combined with toluene and xylene were nine times more likely to develop severe Raynaud’s phenomenon.

Skin discoloration caused by Raynaud’s phenomenon, which can also lead to necrosis and gangrene. (Image sourced from

“I am concerned that 75% of those who worked with xylene or toluene handled wet sample slides without gloves. The majority had done so daily for over a decade,” said lead researcher Gordon Purdie, BSc, who is a biostatistician. “Absorption through the skin is a classic way for solvents to have a negative impact on health.”

As those working in histology or cytology labs know, these solvents are used during tissue processing to produce microscopic slides for viewing by pathologists. Researchers concluded that constant exposure to solvents is a contributing fact in the increased cases of Reynaud’s phenomenon among the study’s participants.

According to the study, medical laboratory workers who did not handle solvents developed severe Reynaud’s phenomenon at the same rate as people who did not work in medical laboratories at all. The researchers could therefore conclude that the increased incidence of Reynaud’s phenomenon cases among histology and cytology laboratory workers was the direct result of exposure to solvents.

Symptoms of Raynaud’s Phenomenon

Traditionally, Raynaud’s phenomenon results from exposure to cold or emotional stress that causes blood vessels in the hands, feet or other extremities to spasm. The alternating constricting and dilating of the vessels are called vasospastic attacks. They decrease the blood flow to those areas resulting in discoloration, and in extreme forms, can cause the skin to atrophy and lead to gangrene and necrosis.

This is the first study to demonstrate a link between medical laboratory worker solvent exposure and symptoms of auto-immune connective tissue disease, and has important implications for workplace health and safety,” said Andrew Harrison, Ph.D., a Senior Lecturer in Rheumatology at the University of Otago, and co-author of the study.

Study May Encourage Pathologists to Adopt Alternative Processing Methods

It is likely that this new study by the researchers at the University of Otago will motivate other researchers to also study the health impact of working with the solvents and chemicals commonly found in histology and cytology laboratories. The use of these chemicals for purposes of tissue processing and fixation is widespread. Thus, the findings of this study, if confirmed by future studies, will likely spur pathologists and histology laboratory managers to take steps to reduce staff exposure to these chemicals.

There are alternative methods for processing and fixing tissue that do not involve the chemicals that were the subject of the University of Otago study. One company that is a pioneer in developing automated tissue processing systems that don’t require formalin and similar chemicals is Milestone Medical. It offers an automated tissue processing system that allows the operator to choose “formalin or formalin-free fixation” and “xylene or xylene-free clearing.”

Milestone Medical may be among the first of the histopathology companies to recognize the demand by some histology laboratories for automated processing solutions that reduce the staff’s direct exposure to chemicals. But with this study, which links exposure to xylene and toluene to a higher incidence of Raynaud’s phenomenon, it is likely that more pathology laboratories will now want to look at how to reduce staff exposure to these chemicals—and possibly even eliminate their use.

Pathology groups and histology laboratories will probably also want to assess how this new research study might change the legal liability that the laboratory has, as it pertains to employees who have decades of exposure to xylene, toluene, and similar chemicals, and who may also show the symptoms of Raynaud’s phenomenon. In the United States, it doesn’t take long for attorneys to recognize a new legal cause of action and begin advertising to find individuals willing to be the plaintiff in a lawsuit.

Finally, it must be acknowledged that there is already a growing trend to re-design histology and cytology laboratories so that the odor from these chemicals is eliminated. In addition, enhanced use of automation and workflow redesign techniques reduces the direct exposure lab staff has to such chemicals. The findings from this new study linking use of xylene and toluene to Raynaud’s phenomenon may serve to accelerate this trend, for all the right reasons pertaining to staff safety.

Related Information:

Health Risk from Solvent Use by Lab Technicians (Press Release)


Questions and Answers about Raynaud’s Phenomenon

Comparison of Formalin-Free Tissue Fixatives: A Proteomic Study Testing Their Application for Routine Pathology and Research

Comparison of Formalin-Free Tissue Fixatives: A Proteomic Study Testing Their Application for Routine Pathology and Research (Archives of Pathology & Laboratory Medicine)

16 responses to “Health of Pathology Laboratory Technicians at Risk from Common Solvents like Xylene and Toluene”

  1. Ajit Alles says:

    This study looked at two organic solvents. The xylene/toluene free alternatives are also organic solvents- they have to be to remove paraffin or to permit transition from alcohol to paraffin. There is no evidence yet if these alternatives cause the same harm that the traditional solvents do. Be cautious about jumping on the bandwagon.

  2. Mutaz Ali says:

    I agree and this matches with our experience in Africa

  3. Linda Flynn says:

    I read this article with strong interest. I worked in very close proximity to a Histology area for over seven years and I developed Raynaud syndrome. It was quite bad. Since I am “out of the lab” and not exposed, my symptoms have abated and I only have a rare episode. I never made the connection.

    Thank you for this interesting article.

  4. Rebecca says:

    Thanks for publishing this article. I am a former Histotechnologist. I retired in 1997 after seven years in the Pathology laboratory to start a family. This year, 2011, I noticed my fingers starting to lose color in them periodically when they were chilled. It was very puzzling. After reading the findings in the research it was very settling and disturbing all at the same time. I have talked to several doctors about the discoloration and even showed them pictures from my phone. All of them thought it was Raynaud syndrome and all were puzzled as to why it would occur.

  5. Sheila W. says:

    I was interested to see this article. In Canada there are Occupational Health and Safety laws that require labs to use these chemicals with extreme care. This includes the use of safety cabinets and extractor fans, as well as wearing gloves. Your suggestion to eliminate their use is of course the ideal alternative, but as you know change does not come easily in pathology labs! Even the labs we are working with in Tanzania are mostly using extractor systems for the fumes and also monitoring the environment periodically to determine the level of exposure.

  6. Wolfgang M. says:

    I have read the article quite interested since I am/was working for a long time (now for ~ 35 years) in Labs using the two solvents, as well as other, more hazardous chemicals!). My reply on this “might not” fit well into common sight but: first of all it is the responsibility of Lab heads/supervisors to ensure safe working for all staff personell with chemicals used in such facilities (especially if employed people working with such are not experienced or don’t have the necessary ‘chemical’ knowledge background for safe handling of these). Secondly, there is – at least in Europe – harsh legislation as well as there exist rules, respectively, how to handle the matter. Also staff people working in such facilities (histology, pathology labs) are (by laws) requested – at least once in a year – to get examined their blood on levels for at least xylene. Needless to say that toluene as routinely used chemical (like CCl4 or ether as well) more / less has/have been banned from “modern” lab facilities but for “very” specific tasks it MIGHT be necessary to use that stuff. But then – normally – I am sure about a specific knowledge of the user with such a chemical and how to protect himself against the breathing, and cutaneous absorption hazard: personal safety wearings: use of suitable=chemically resistant gloves, safety goggles, fume-cupboards etc. It is ok if companies be at liberty to advertise their products, also with a background of “making your working area” safer (e.g. in terms of automated processing, also presenting/using chemicals supposed to be “healthier” than others) but it MIGHT also turn out that use of such is – pardon me – similarly hazardous (for most only limited data on their effects to living, human, ‘organisms’ are available). So for me finally it is not a question of only buying highly sophisticated equipment connected with certain kind of “tested company fluids” (especially in the ‘third world’) and forget about personal health risks BUT rather a question of good education, acquisition of good-specific knowledge about as well as personal sensibilization against exceptable jeopardies (even if they seem to be hidden) in our “Specialty” Labs.

  7. Dr.Ashwini says:

    I am a medical doctor. I am undertaking a reserach study for documenting the prevalence of morbidities among clinical labaratory staff (doctors, lab technicians, clerical staff and housekeeping staff). Could you let me know any pertinent studies on this subject.
    Bangalore, India

  8. Glenda Bollivar says:

    I work in Halifax Nova Scotia and have recently been diagnosed with systemic sclerosis (scleroderma). I have worked in a pathology lab my entire life…>30 years. My symptoms started many years ago, but recently the GI issues and fatigue have made it unbearable to work. I have applied, and been denied twice, an application for Long term disability. Part of the problem is that scleroderma can be difficult to diagnose (little objective evidence), and the fatigue (since it is subjective), is often overlooked. Believe me, this whole experience has been very disheartening. I often wondered in past years whether anyone had looked into the health issues of pathology lab workers. In my lab alone, we’ve had one tech leave with multiple sclerosis, another with lymphoma. There also seems to be a high rate of psychiatric problems in the children of my co-workers. Anyway, good to see that someone is doing some research into this.


  9. καταπολεμηση κυτταριτιδα says:

    whoah this blog is magnificent i love studying your posts. Keep up the good work! You recognize, a lot of people are hunting round for this info, you can aid them greatly.

  10. CAN KUCUKAKSU says:

    Hello Iam a medical doctor in Turkey .I am working in occupational disease hospital in Istanbul.we are undertaking a study for documenting the prevalence of morbidities among patology labaratory and anatomy staff (doctors, lab technicians and housekeeping staff). We measured Formaldehyde and Xylene on air of the laboratories.We also measured metabolites of formaldehyde and xylene in staff urines.Can you help me this subject for document or morbidity e.t.c.Thank you


  11. Gemechu Ameya says:

    I am very interested with issue which is affecting us who was working in pathology laboratory. I was working in pathology laboratory of Hawassa University College of medicine and health science but there is no such awerness. And there is difficult of gateing enough IP like eye gogles and otheres. there is no training conserning this one please reach for us b/c we are hurting our Life when serving others!!

  12. For those interested in the morbidity of technicians/technologists working in the field of Histotechnology, there was a study done a few
    decades ago. I am at a loss to give a reference,
    but not at a loss to apologise for this.
    My recall is that the average age was 40 for both men and women. Quite a startling statistic.
    However, in my own exposure to this laboratory
    discipline, caution and care was part of the training ( thank you Jim Griffin )and not one person developed Raynaud’s phenomenon, as far as I am aware.I am also of the strong belief that
    technicians are not being taught properly and that professional technologists are a rarity these days. This could also account for the incidents referred to in the previous posts.

  13. Peggy says:

    Thank you for this article. I am a much older histotech who worked with all the above chemicals before OSHA even cared about our welfare. This meant no gloves (the pathologist would make fun of us if we wore masks or gloves), no ventilation, no goggles, no warning. I have begun having long lasting severe feet and leg cramps for which I and my doctor have not been able to find a good reason. I think in this article I could have found the reason.
    Again thank you, I will bring this up to my Internist.

  14. Margaret says:

    I have been a cytotechologist for the past 32 years. I vconsulted an ENT specialist due to deafness and tinnitis in the one ear. ANF test was done and the titre was >2024. Immunological studies were done and I was diagnosed with CREST syndrome. Lately I also developed musculoskeletal problems and thought it was possibily attributed to the long hours behind a microscope. Thank for this article. I certainly was an eye opener and I will bring it to the attention of my employer’s HSR.

  15. Bonnie Edwards says:

    This was interesting to me especially. I have a little different circumstance. I was a histotech and our tissue processor was malfunctioning one night ended up mixing the chemical lines, combining xylene and formalin together. When I opened it to take out the specimens after processing, the mixture of the 2 exploded on release of the seal. I was severely burned in my eyes, nose, mouth and sinuses. After many months of time off and being told by ENT that I was unable to work in the lab again, I have had to live with chemical and environmental allergies since (greater than 20 years). Now I was just re-endoscoped and I have now developed holes in my sinuses that will now have to be surgically repaired. Amazingly, my sinuses are still showing signs of the original burns, even after 20 years. I also have developed cataracts, severe degenerative arthritis and other potential connective tissue problems. I am only 55 and have already had both my knees replaced more than 5 years ago, need my hips done and have numerous cervical and lumbar disc problems. I believe that this is all related to the chemicals. I was very healthy until my accident. I do not know of anyone else who has had an acute exposure to the chemicals in pathology, mostly long term exposure as do I. We never used gloves when staining and drying the slides as the chemicals would melt them and we would get gooey stuff on the slides themselves. I loved my old job, but not in love with the side effects of it.

  16. Ian Spensley says:

    I worked in a quarry laboratory testing macadam’s by washing tar and bitumen from samples in order to confirm the percentage of binder and then be able to check the gradation of the aggregate against British Standards. We used xylene in retorts under re-flux to constantly washed the binder from the sample inside the retort. For many years I have suffered with chronic fatigue which has been diagonsed as Fibromyalgia. It was the 1970’s when we used this method, since then we changed to using methylene Chloride. My symptoms continue to get worse and I’m convinced that exposure to xyelene was the trigger

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