Safety: A to Z (Part II)


Working as a histo-technologist or histology technician has been recognized as potentially damaging to health. The US Department of Labor’s Occupational Information Network identified exposure to hazardous conditions, to contaminants, and to disease and infections as the top 3 health risks for these professions.

Erhalten Sie neueste Informationen aus dem Knowledge Pathway direkt in Ihr Postfach.

Wenn Sie sich dieses Schulungswebinar aus unserer monatlichen Reihe angesehen haben und dessen Anerkennung als Weiterbildung seitens der Sie zertifizierenden Organisation beantragen möchten, füllen Sie bitte das Formular aus, um Ihrem Protokoll die entsprechenden Weiterbildungspunkte gemäß Ihren eigenen Angaben hinzuzufügen.


Learning Objectives :

  1. Examine the A-Z approach of topics in safety.
  2. Review the day to day dangers that qualifies the Histotechnology career to be one of the most dangerous jobs.
  3. Prepare for the Qualification in Laboratory Safety examination.

Webinar Transcription

Allison is the lead histotechnologist at Doylestown Hospital in Doylestown, Pennsylvania. She has been a histotechnologist for 15 years after graduating with a degree in histotechnology through Harvard Community College in Maryland and a bachelor's degree in biology from Lycoming College in Pennsylvania. She holds her qualification in laboratory safety certifications through the ASCP, as well as her Allied Health Instructor certification through AMT.


Let's go ahead with safety A to Z part II. The objectives are to examine the A to Z approach of topics in safety and review the day-to-day dangers that qualify histotechnology to be one of the most dangerous jobs. Topics covered will help you to prepare for the QLS exam.

The idea behind this webinar was a study published by the U.S. Department of Labor indicating that histology was the most damaging career to your health. The Department of Health used three categories to devise an overall unhealthiness score, which included exposure to hazardous conditions, exposure to contaminants and exposure to disease and infections. They came up with an overall unhealthiness score of 63.8 for histotechnology, making it the most damaging career to your health. We are aware that hazards exist in the lab, but this will take an alphabetical approach to some of the different topics.

K = Kindness

We will start with K. Few safety topics start with K, so first is kindness. Kindness may not seem like a safety topic, but it is. Kindness contributes to the overall morale of the department. Distractions from someone's poor or hostile attitude cause unclear thinking and overlooking of small safety items. Consider disgruntles employees and workplace violence. I spoke last session about being ready in an active shooter situation. While that situation is not always preventable, being kind is a really great place to start. Most of us spend more time with our coworkers than we do with our own families, so we should make an effort to be kind to our coworkers.

L = Labeling

L is labeling, for the Globally Harmonized System (GHS) labeling. We could spend the whole hour talking about this topic alone. GHS was set in place by OSHA with the primary purpose of education and standardization. It is an international system developed to replace the variety of hazardous material classifications. International travel and transit has become more prevalent, so having different hazard classifications has become increasingly confusing. GHS core elements include standardized warnings, pictograms for hazardous classifications, and harmonized data sheets that include the same 16 points all in the same order. OSHA developed training guidelines and institutions and companies with hazardous waste or chemicals should be in compliance with GHS labeling. Guidelines now require primary containers to be labeled in a standard way, but any secondary containers have to be labeled the same way as well. A container once labeled as 5% periodic acid, must now be labeled exactly like the primary containers.

M = Monitoring for Chemical Exposure

CAP accredited labs are familiar with ANP.08216, which is the formaldehyde and xylene safety checklist question. Formaldehyde and xylene vapor concentrations are maintained the following maxima, expressed as parts per million in all areas of anatomic pathology where formaldehyde and xylene are used. Employees who may be exposed to these chemicals should be identified and monitored. CAP says the lab can discontinue periodic formaldehyde monitoring if two consecutive samples taken a week apart show employee exposure is below the action levels and the short-term limits. With xylene, there is no requirement for periodic monitoring after initial monitoring. I personally don't agree with that. Things can change such as ventilation, and we may not be aware of it until it is too late. I monitor once a year, which we find to be the best and safest way.

One thing to look at is the short-term exposure limit (STEL), which is exposure over 15 minutes; time-weighted average (TWA); and action level. The OSHA guideline for formaldehyde over 8 hours is 0.75 parts per million and goes up to 2.0 parts per million in 15 minutes. Xylene is substantially higher at 100 parts per million over 8 hours and 150 parts per million over 15 minutes.

N = Needle Sticks

Needle sticks are generally considered accidental exposures, but can also include injuries from broken glassware. Needles need to be disposed of in impervious disposable containers, which need to be located directly near where needles are being used. For an outpatient draw station, the sharps containers need to be directly in the draw station. The OSHA bloodborne pathogen standard requires employers to implement an exposure control plan for the worksite with details on employee protection and measures. There are a lot of different options for safety engineered devices for needles, which should definitely be investigated. Bending, recapping, or removing contaminated needles should be prohibited as general practice.

General first aid for needle sticks first requires stopping the bleeding and flushing the wound with water, which will neutralize any hazards. You should consult medical attention or go to occupational health or your emergency department if needed. A tetanus booster should be given if needed. The wound should then be dressed and wounds greater than 1 inch or those that do not touch may require stitches.

O = Office Safety

The image shown reveals unsafe things happening. First, there is an extension cord running along the floor, which is a trip hazard. Boxes in the walkway are also a trip hazard and will not allow for exit in case of emergency. Here somebody has left one of the filing cabinets open, which can be a trip hazard. We actually had someone leave the upper cabinet open and step away for 2 seconds to do something. Then somebody came around the corner, hit his or her head, and actually got a concussion. Even if you're coming right back, make sure you close the filing cabinet. Here we have some boxes that are piled pretty close to the ceiling. Allow at least 18 inches between the top of what you're storing and the sprinklers to maintain efficiency of sprinkler systems. Here is a paper cutter up that should always be closed and shielded when not in use. Here we have a space heater. Space heaters should not be used in histology at all, but if you're going to be using them in an office setting, make sure that they are approved for commercial use.

P = Pregnancy

Pregnancy in the lab is something that comes up pretty often. We can't rely on OSHA for pregnancy guidelines in a histology laboratory. Exposure limits don't apply to pregnant women, so what can you do? The first thing to do is have your OB involved in determining what is safe. When I was pregnant, I brought to my OB a list of all the chemicals in the laboratory, as well as the SDS. I left it to him what is safe and what is not safe. After discussion between us and involving a genetic counselor, we came up with a short list of what is prohibited for a pregnant woman. Xylene is prohibited. Ammonium hydroxide is a reproductive toxin, so should be prohibited. Hemotoxylin should also be prohibited, as well as any dry chemical, due to inhalation hazards. Formaldehyde may cause genetic defects, but can be used with caution and proper PPE. I continued to gross until the day I left on maternity leave.

Your OB may decide to consider you high risk due to chemical exposures. Also, you want to keep your supervisor informed. Accommodations have to start as soon as you find out that you're pregnant. They must make accommodations for you. Since reproductive toxins are in the lab, accommodations must start immediately, especially during the first weeks of organ formation. Most importantly, you're ultimately responsible for you and your baby. If you don't feel comfortable with a certain test or working with a certain chemical, you should have a conversation with your supervisor immediately. From my experience, people are generally helpful to their fellow employees.

Q = Quantity (EPA Generator Status)

EPA generator status is based on the amount of hazardous waste every month, which is all waste accumulated at your site, including pharmaceutical waste and regulated medical waste from the operating room and floors.

There are three categories. There is very small quantity generator, which used to be known as conditionally exempt, and produces less than 220 pounds of waste per month and less than 2.2 pounds of acute hazardous waste per month. The acute hazardous waste includes P-listed waste, which is generally pharmaceutical waste such as nicotine, warfarin, and nitroglycerin. There are no limits to onsite accumulation or quantity limits for very small quantity generators. Generator requirements don't apply here.

Next are small quantity generators, which produce between 220 and 2,200 pounds of waste per month. Onsite accumulation time is 180 days or 270 days if disposal site is greater than 200 miles away. At the last session I talked about the RCRA guidelines. Here you play into this quantity generator and your waste hauler decision. The onsite quantity limit cannot exceed 13,200 pounds. Small quantity generators should have an EPA ID number and waste packaged in DOT-approved containers that are properly labeled with the proper markings and accumulation start dates. The 180 days starts from the time you place your first drop of waste into the barrel. This waste is then sent to an EPA-permitted treatment storage and disposal facility. Generator requirements apply and mandate an emergency coordinator, as well as hazard prevention and personnel training plans. Signed manifests and waste analyses must be kept for 3 years.

The third generator status is large quantity, which are four generators that produce more than 2,200 pounds of waste per month and more than 2.2 pounds of acute hazardous waste per month. Onsite accumulation time must be less than 90 days, but there are no onsite quantity limits. Large quantity generators abide by the same regulations as the small quantity, with the additional requirement of submitting a report every 2 years summarizing types and quantities of hazardous waste use, methods of disposal, and efforts made towards waste reduction and the efforts of those wastes.

If a generator teeters around the 2,000-pound mark, it could be considered an episodic generator if the waste is not constant. It can fluctuate between very small and small or small and large. Then the generator requirements apply for that month, depending on what your generator status is.

R = Respiratory Protection

Respirators and masks are different, so you have to make sure to choose the proper protection for what you need protection from. Surgical masks and dust particulate masks are not considered respirators, but will protect you from airborne pathogens. Respirators are used to prevent exposure usually to chemicals. Those using respirators should be fit tested every year. I believe you cannot have a beard if you are using a respirator. Respirators should have appropriate filters, such as protection from formaldehyde or xylene requires a filter for organic vapors.

Engineering controls is the best way around needing a respirator or fit testing. We used to have a PAPR respirator, which is basically the top half of the hazmat suit. It was used for disposing pathologic waste, where the formalin was separated from the body tissue. We found a company that took everything together, so we no longer had to separate anything and no longer needed any respiratory protection.

S = Spill Response and Decontamination

There should be a written policy for the safe and appropriate response to accidental release or spill of hazardous materials. This is essential for safety of employees, patients, and visitors. The policy can be written by the lab or in conjunction with your Environmental Health and Safety or Environment of Care Departments.

Spills are divided into minor and major spills. A minor spill is less than 5 ml of hazardous material or any spill that can be cleaned up by people who have training and PPE available on hand. A spill kit should be onsite for cleaning a minor spill, but there are a lot of different types of spill kits, so make sure you have the appropriate spill kit for what materials you would possibly have to clean up. There is a general spill kit or all-purpose spill kit, which is designed to handle most non-hazardous liquid spills such as coolants, solvents, or antifreeze. There is the hazardous waste or hazmat spill kit, which is good for cleaning up hydrocarbons, petroleum distillates or any other kinds of acids or solvents. Then there are biohazardous waste spill kits, which are used for cleaning up primarily body fluids such as blood, vomit, feces or urine. All spill kits contain materials to clean the spill, to package it up, and to dispose of it properly.

A major spill is anything over 5 ml or beyond the training and PPE available, which can represent an immediate danger to personnel. The 5 ml is a very small volume and is not written in stone. Use your judgment. I think most people in histology that spill 5 or 10 ml of formalin on the floor are definitely equipped to clean that up. Definitely use your best judgment in that case. You may need to have a hazmat team available in the case of a major spill, which can be hospital-based and is usually comprised of employees of the hospital who are trained to clean up spills. You might also have a fire company's hazmat team available for you.

If you have a spill, evacuate the area, notify your spill response team of the material that spilled, and provide an SDS if possible. The spill response team will don proper PPE and probably use Draeger tubes or meters as needed. Use absorbent materials and universal neutralizers for small spills, but for large spills, dike the area and then neutralize. When using a neutralizer, start from the outside of the spill and work your way in. That will keep it from spreading. Then dispose of all neutralized materials in accordance with your local laws.

The most important thing to remember is at all times entry to a hazmat environment should be conducted by one trained associate with one trained associate standing by. Never enter a hazmat situation alone, in case something happens while you're in that situation.

T = Tissue Fixatives

There is a variety of tissue fixatives. They are generally not great for your health. They are carcinogenic and can be reproductive toxins, highly toxic, or corrosive. Carcinogenic fixatives are among the most hazardous of substances used, but we work with them every day. We should be using a hood and wearing gloves, lab coats, and safety goggles to protect us. Formaldehyde is a carcinogen and a strong sensitizer. It is harmful if inhaled or absorbed through the skin. High exposure to formaldehyde can be fatal and it can cause blindness if swallowed.

Glutaraldehyde is another fixative used that corrosive and can cause severe eye burns, as well as severe irritation to the skin and respiratory tract. Potassium permanganate, potassium dichromate, and osmium tetroxide are strong oxidizers that can cause severe burns to any area of contact and are potentially fatal if swallowed or inhaled. Potassium dichromate is a known carcinogen. Mercuric chloride is fatal if swallowed and can cause birth defects, as well as harmful if absorbed through the skin and can cause severe irritation to the eyes, skin, and respiratory tract. Mercury should be essentially eliminated from most laboratories now. Your best route of protection is to make sure you wear proper PPE while working with any of these.

U = UV Light and Radiation Safety

This is becoming more and more prevalent in histology due to cryostat decontamination. Radiation is essentially energy that travels through space. For non-iodizing radiation there are three categories. Black light is between 315 and 400 nm. It is used in tanning beds and voncaso [phonetic] silver stain. The mid range is 280 to 315, which can cause sunburns and cataracts. Then 100 to 280 is the range for decontamination for cryostats. It is important to have proper signage and proper education for employees to know how to remain safe when using UV light.

V = Ventilation (Hoods, BCHS, Negative Air)

OSHA standards for ventilation are old, written in 1990 and contain a broad room exchange rate. It can be anywhere from 4 to 12 exchanges per hour. The more recent ANSI standards are vague and leave the room exchange rate up to individual facilities. Section 2.1.2 requires that specific room ventilation rates are established by the facility owner. Section 2.1.3 states dilution ventilation shall be provided to control buildup of fugitive emissions and odors in the laboratory, but a good range of exchange rates is not given.

There are two kinds of hoods. They look the same on outward appearance, but are different and have different uses. First is the fume hood. The most common is constant air volume ducted hood, which vents unhealthy air out of the lab through a chimney, and should be used with chemicals and non-biologic hazards. A fume hood will not offer protection from something biologic in nature.

Next is the biologic safety cabinet, which is used to protect from biologic hazards, but will not protect from any type chemical or non-biologic hazard. There is a Y classification of different types of biological safety cabinets depending on what you are working with. The higher the safety level needed, the higher the biologic safety cabinet needed.

Histology laboratories can be negatively pressured, and this basic diagram explains negative air pressure well. A room with negative pressure will suck air into the room when the doors or windows are opened, which will prevent microorganisms and contaminated materials from escaping through open doors and windows. It will also reduce the hazardous vapors that escape into public spaces. As the doors open, passive air moves in and then the air gets sucked out through the ventilation system.

W = Waste Compatibility and Storage

Hazardous waste is waste with properties that make it dangerous or capable of having harmful effect on human health or the environment. Characteristic waste is waste that exhibits one or more of the following characteristic properties: ignitability, corrosivity, reactivity, or toxicity.

Reactivity is unstable compounds that react violently with water or compounds that give off toxic gasses when mixed with water or capable of detonation of explosion under normal conditions. This might be chromic acid, picric acid or ammonical silver.

Toxicity is toxic waste that is harmful when ingested or absorbed. When toxic waste is land disposed, contaminated liquid may leach from waste and pollute ground water, which is why it is important to have a certified disposer. Toxic waste might be chloroform, chromium, mercury or silver.

Ignitability is anything that has a flash point over 140 degrees. This might be acetone, acetic acid, xylene or xylene substitutes, ethanol greater than 24% or methanol.

Corrosivity is anything with a pH greater than 2 or 12.5, which corrodes steel at a rate of a quarter inch per year, so this waste should not be collected in a metal container. Examples are 1% acetic acid, 1% hydrochloric acid, periodic acid, chromic acid, and ferric chloride.

There is a CAP general guideline for acid and base storage. Supplies of concentrated acids and bases should be stored separately and bottle carriers should be used to transport glass containers larger than 500 ml containing hazardous chemicals. Storage should be below eye level and not under the sink. Acid burns are no joke. These are pictures of a British model who was burned when a stranger threw sulfuric acid at her face during an attack. The pictures were taken 43 days after the attack.

X - Xylene

Xylene is a clear, colorless solvent that can be any combination of isomers. We want to monitor our exposure in the laboratory. OSHA limit is 100 parts per million over 8 hours, but we can detect the smell of xylene as low as 0.8 to 3.7 parts per million. It can cause headaches , is a skin irritant, and is non-carcinogenic, non-teratogenic, and non-mutagenic. Pregnant and nursing women should minimize xylene exposure, as it can reach a developing fetus and contaminate breast milk.

Y = Yersinia/Yellow Fever

Yersinia pestis is a Gram-negative, rod-shaped bacteria with no spores commonly known as the plague or the bubonic plague. It is transmitted via flea bites, contact with contaminated fluid or tissue, or infectious droplets. We tend to think of the bubonic plague as being something from history, but it is still quite prevalent in the United States, particularly the southwestern corner, northern New Mexico, northern Arizona, Colorado, California, southern Oregon and Nevada. Over 80% of U.S. plague cases are of the bubonic variety, about 17 cases per year.

Z = Zika

Zika has fallen outside of the news, but it is still around and still causing some problems. It is vector borne and is caused by mosquito bites. There has been some discussion that formaldehyde will inactivate the virus, so we don’t need to be concerned when working with tissue of Zika-infected patients. Make sure that the placenta is completely submerged and kept in formalin up to 72 hours until worked up. The placenta tends to be harder to fix completely, so complete fixation should be reached before starting to dissect it.

I want to acknowledge OSHA Safety, as well as Donna Chudley at St. Luke's Hospital, who contributed to this webinar.

Questions and Answers

Q: Why would space heaters not be used in histology labs? My room barely gets to 70 degrees Celsius in Wisconsin.
A: That is a combustion issue, a fire hazard. I am in Pennsylvania and it seems it is freezing in my room almost all the time. It is a fire hazard with all the chemicals around, so be sure to avoid space heaters around the chemicals.

Q: Are there any xylene substitutes that you would recommend?
A: The answer is no. I've tried a bunch of them. They all have their good points, but are not without their own risks. Working safely with xylene is probably the gold standard, but that's just my opinion.

Q: Do you see any issue with vapor monitoring more often than CAP recommends?
A: While it might be a pain to do, I think it is beneficial. Also, you demonstrate that you care about your employees by doing it. Things can change in your ventilation or something can happen with an instrument that you might not be readily aware of that can be picked up in vapor monitoring.

Q: Are there any resources for a pregnant histology worker to use when speaking to her supervisor?
A: There really has not been a lot of research done about that. The NSH has some good resources. A good place to start is to work with your OB. You can also involve a genetic counselor.

Q: Is the dust of paraffin cuts dangerous? Should we be wearing a respiratory device when cutting?
A: No, I don’t think so.

Q: Should histology labs be under negative pressure?
A: I am not aware that it is a requirement by OSHA or anybody. My department is under negative pressure, as well as the morgue, but it may be a local requirement. You should check with your Environmental Safety Department. They would probably know better.

Q: I am a pathology registrar in an underdeveloped lab. Our fume hood cut-up room and PPE for us, and our scientist is poor. Where should we start from, fume hood or proper PPE?
A: Both are important. You definitely want to have good ventilation to help draw formaldehyde vapors away from you. It is hard to gross while wearing a respirator and if you have to dictate while doing that. You will want to get some sort of fume hood or ventilation. Then you definitely need to have PPE to keep you safe from contact with the vapors and formaldehyde.

Q: Regarding cryosectioning, do you disinfect the cryostat with UV light? How do you normally deal with that from a regulatory point of view?
A: The cryostat will have a UV light inside of it. It is not something that is added or on purchased separately. It disinfects all of the visible surfaces. You also have to do a decontamination to be in accordance with CAP. It's two separate issues.

Q: Do you recommend having snorkels or down drafts tested for air velocity?
A: I don't know what a snorkel is, so I don't know how to answer that. We don't test our air velocity, but if it is noted it is not working as well, that is the indicator that something might need to be cleaned.

Q: Should histotechnologists get rabies vaccinations?
A: I don’t know. I would say if you worked in a lab where you're potentially at risk for rabies, such as working with animal tissue, maybe. I don’t think in a clinical situation it is necessary. I don’t know.

Q: Should we be concerned if our silver jewelry is tarnishing in the lab during an 8-hour period?
A: I don't know how to answer that question. It's a really good point, but I don't know. It's nothing I've ever encountered or thought about.

Q: Are there specific plans for histology available? My lab was built without ventilation and I have to submit a plan for the lab.
A: I'm not sure. I would imagine there are a handful of histology lab consultants who probably have experience in building laboratories. They would definitely know the requirements of how to submit a blueprint of that.

Die Inhalte des Knowledge Pathway von Leica Biosystems unterliegen den Nutzungsbedingungen der Website von Leica Biosystems, die hier eingesehen werden können: Impressum. Der Inhalt, einschließlich der Webinare, Schulungspräsentationen und ähnlicher Materialien, soll allgemeine Informationen zu bestimmten Themen liefern, die für medizinische Fachkräfte von Interesse sind. Er soll explizit nicht der medizinischen, behördlichen oder rechtlichen Beratung dienen und kann diese auch nicht ersetzen. Die Ansichten und Meinungen, die in Inhalten Dritter zum Ausdruck gebracht werden, spiegeln die persönlichen Auffassungen der Sprecher/Autoren wider und decken sich nicht notwendigerweise mit denen von Leica Biosystems, seinen Mitarbeitern oder Vertretern. Jegliche in den Inhalten enthaltene Links, die auf Quellen oder Inhalte Dritter verweisen, werden lediglich aus Gründen Ihrer Annehmlichkeit zur Verfügung gestellt.

Vor dem Gebrauch sollten die Produktinformationen, Beilagen und Bedienungsanleitungen der jeweiligen Medikamente und Geräte konsultiert werden. Leica Biosystems und die Herausgeber schließen hiermit jegliche Haftung für Verluste oder Schäden aus, die sich direkt oder indirekt aus der Anwendung des Inhalts ergeben könnten, einschließlich der Anwendung von Medikamenten, Geräten, Techniken oder Verfahren, die im Inhalt beschrieben sind.

Copyright © 2021 Leica Biosystems als Teil der Leica Microsystems, Inc. und Partnerunternehmen von Leica Biosystems. Alle Rechte vorbehalten. LEICA und das Leica Logo sind eingetragene Warenzeichen der Leica Microsystems IR GmbH.

Möchten Sie, dass wir von Ihnen verfasste Texte veröffentlichen?

Wir sind stets auf der Suche nach weiteren interessanten Autoren, die wir hier vorstellen möchten. Reichen Sie Ihren Beitrag ein und wir melden uns bei Ihnen!

Reichen sie ihr Manuskript ein.

Mögen Sie, was Sie sehen?

Erhalten Sie mehr Inhalte aus dem Knowledge Pathway direkt in Ihr Postfach. Sie können sich jederzeit wieder abmelden.