Occupational Exposure to Trichloroethylene: Industrial Solvents

1024px-Trichloroethylene-3D-ballsAccording to chemical summary published by the EPA, trichloroethylene (TCE) is a volatile organic chemical used primarily as an industrial solvent. TCE is a colorless or blue liquid with a sweet, chloroform-like odor. The most common use of TCE is to remove grease from fabricated metal parts and some textiles. It is also an ingredient in adhesives, paint removers, typewriter correction fluids, rug-cleaning fluids, spot removers, and pepper sprays.

Because TCE readily evaporates at room temperature, it is important for workplaces that use this chemical to provide appropriate monitoring devices and room air filtration to protect workers from overexposure.

Hazards of Trichloroethylene

The International Agency for Research on Cancer (IARC) classifies Trichloroethylene in Group 1 – Carcinogenic to Humans. Many cancers have been evaluated, but there has been a focus on tumors of the kidney, liver, and non-Hodgkin lymphoma.

Noted below are some excerpts from the Agency for Toxic Substances & Disease Registry’s Public Health Statement for Trichloroethylene:

  • Exposure: Trichloroethylene in air can easily enter your body when you breathe. Most of the trichloroethylene that you breathe in will go into your bloodstream and into other organs. A small amount of trichloroethylene in the air can also move through your skin and into your bloodstream.
  • Health Effects: Once in your blood, your liver changes much of the trichloroethylene into other chemicals. The health effects of trichloroethylene depend on how much trichloroethylene you are exposed to and the length of that exposure.
  • Long Term Effects: Exposure to trichloroethylene in the workplace may cause scleroderma (a systemic autoimmune disease) in some people.
  • Short Term Effects: People who are overexposed to moderate amounts of trichloroethylene may experience headaches, dizziness, and sleepiness; large amounts of trichloroethylene may cause coma and even death. Some people who breathe high levels of trichloroethylene may develop damage to some of the nerves in the face. Other effects seen in people exposed to high levels of trichloroethylene include evidence of nervous system effects related to hearing, seeing, and balance, and changes in the rhythm of the heartbeat, liver damage, and evidence of kidney damage.

Occupational Exposure Limits

Several health and safety agencies provide recommended or mandatory exposure limits for trichloroethylene. CAL-OSHA and NIOSH both recommend a 25 ppm limit TWA. This means that within an 8 hour shift the average concentration of TCE cannot be more than 25 parts per 1 million parts of air.

While all employers are required to meet the OSHA PEL of 100 ppm, many companies have adopted stricter exposure limits in light of newer studies and research on TCE’s health effects.

Occupational Exposure Limits: Trichloroethylene
100 ppm TWA 25 ppm TWA 25 ppm TWA 10 ppm TWA

Source Capture Vapor Control

The idea of capturing fume at the source of emission is called “source capture”. Source capture filtration systems work to pull harmful fume and dust away from the operator’s breathing zone before inhalation of these hazards can occur.

Usually placed within five inches of the source, these systems draw contaminated air away from the operator and into either a recirculating filtration unit (ductless) or out through a building’s exhaust system (ducted).

Sentry Air offers several configurations of ductless source capture fume extraction. Depending on the application, we have benchtop units, wall mounted units, and floor units.

Some of our most popular items for parts cleaning and solvent use are our Ductless Fume Hoods, Downdraft Benches, and Wall Mounted “Sky” units.

ductless containment hood, ductless fume hood

Ductless Fume Hoods
24”, 30”, 40”, 50”, 60”, 70” Standard Widths
Up to 60 FPM w/ Pre-Filter and Carbon Filter
Custom sizes and features available

Downdraft Benches Table Style Portable Style – Sitting Height (shown) Portable Style – Standing Height Up to 700 CFM


Wall Mounted “Sky” Units Model 300 – up to 350 CFM (shown) Model 400 – up to 700 CFM

Ambient Vapor Removal

Some workplaces and operations may generate what is known as “renegade fume”. Renegade fume is an accumulation of mist, smoke or fume that is found in ambient room air. This can occur in environments that are not adequately ventilated or where several workstations are operating simultaneously.

For example, in an area designated for parts cleaning where solvent use is high, a source capture fume extractor will take the brunt of the work. However, when these parts are placed on open shelving to dry, they will off gas these solvent fumes for hours, thus generating renegade fume.

pracsAs part of a comprehensive industrial hygiene plan, the coupling of source capture fume extraction with ambient room air cleaners offers enhanced filtration and protection from respiratory hazards. Sentry Air Systems has a line of portable and ceiling-mounted room air cleaners for the capture of renegade fume.

One item in particular, the Model 700, offers both HEPA and Carbon filtration for the capture of dust and vapor. The Model 700 can hang from the ceiling, mount to our fume extractor stand, or be placed on a cart for easy portability.

Activated Carbon Filtration

carbonGranule activated carbon is widely known and used for pollutant removal applications like air purification and water filtration.

At Sentry Air Systems, we use activated carbon granules in our carbon filters for the adsorption and filtration of chemical molecules.

There are thousands of granules in our carbon filters and each granule works to adsorb chemical molecules within its vein-like internal structure. As contaminated air passes through the carbon filter, harmful molecules are trapped so that cleansed air is able to recirculate.

On our Activated Carbon Adsorption Ratings chart located on our website, trichloroethylene is rated an “E” for Excellent High Capacity. This means that each pound of activated carbon will adsorb an average of 33 ⅓% of its weight for the specified compound.

Watch a brief video demonstrating how Sentry Air carbon filters work to adsorb chemical molecules.

Contact Us

If your workplace or application uses trichloroethylene or products containing it, speak with a Sentry Air Systems sales specialist for the most appropriate fume extraction solution. Call 800.799.4609, email sales@sentryair.com, visit our website or fill out the feedback form below.


Previous Blog: EPA released final risk assessment on Trichloroethylene (TCE)

Bureau of Toxic Substance Assessment New York State Department of Health: TRICHLOROETHENE (TCE) IN INDOOR AND OUTDOOR AIR

Respiratory Protection during Hormone Pellet Compounding

For years, men and women have turned to hormone pellet therapy for assistance in regulating their body’s hormone levels.

Pellets differ from other forms of hormone therapy, like injections and oral capsules, in that they are implanted underneath the skin for a slow, steady absorption rate rather than an entire dosage all at once.

Larger than a grain of rice but smaller than a Tic-Tac®, these pellets require only a small incision and can last up to 4-6 months.

Investigational Therapy

While many adults experience positive results from pellets, studies have found that their effects are unpredictable and fluctuating.

As a result, the FDA and Maternal Health Drugs Advisory Committee unanimously agreed to terminate compassionate investigative new drug programs for estrogen pellets as a last-resort treatment of menopausal disorder.

Because subcutaneous hormone pellet implantation is considered investigational, there are currently no FDA-approved, commercially available formulations in the United States.

So how does this affect users of hormone pellets? They turn to compounding pharmacists.

Unintentional Hormone Exposure

Depending on the end user, hormone pellets are comprised of either estradiol or testosterone. In some cases these hormones are mixed together into a pellet.

Compounding pharmacists will commonly use a form a trituration to mix the various powdered ingredients together.

Trituration is simply a name for several different methods used to process materials. Process methods can include grinding one compound into another, reducing the particle size of a substance, or producing a homogenous material by mixing component materials thoroughly.

As with any process that grinds powders into a fine state, plumes and dust generate. For compounding pharmacists, these powder plumes pose a health hazard if inhaled.

Imagine the long-term side effects on a male pharmacist who compounds estrogen pellets in his practice. Imagine the same effects on a healthy female pharmacist who compounds testosterone pellets in her practice.

Over time, inhalation of these plumes could have an effect on their own hormone levels. Because of this, it is important for compounding pharmacists to work within a well ventilated enclosure.

PARR Pellet Press System

Pressing Pellets

Once the powdered mix is ready, a small measured dosage is poured into a hand press machine where the powder is compressed into its final pellet form.

In the series of images to the right, a popular commercially-available hand pellet press is being demonstrated.

Between each batch of pellets, the pharmacist may use compressed air to clean the press machine of any residual powders as not to contaminate a new batch.

The process of cleaning the machine with compressed air will also create a small plume of fine hormone powder dust which should not be inhaled. Again, this process should be done within a well ventilated enclosure to protect the pharmacist’s breathing zone.

Powder Containment Hoods

A “well ventilated enclosure” should, at minimum, be comprised of:

  • HEPA Filtration (up to 99.97% efficient on particles 0.3 microns in size or 300 nanometers)
  • Adjustable Airflow
  • Adequately-sized Work Area

A quality HEPA filter has been shown to trap pharmaceutical powders within its paper media and is an industry standard for filtered enclosures.

Regulation of airflow within the enclosure is key to handling powders safely. Too little airflow has minimal to no effect on pulling the dust plumes into the filter media. Too much airflow can cause turbulence within the enclosure and have a negative effect on dosage measurement and powder handling.

An appropriately-sized hood makes working within the enclosure more comfortable and allows the placement of equipment and materials to match the pharmacist’s work style.

Sentry Air Enclosures

Sentry Air Systems has a line of Pharmaceutical Powder Containment Hoods for non-sterile compounding. These ductless enclosures allow pharmacists to safely weigh, measure, and compound prescription dosages.

A powerful fan and filtration system pulls the airborne powder and particulate away from the operator and directly into a HEPA filter. These hoods do not require ductwork or exterior ventilation, making them easy to move around a pharmacy or lab.

A variable speed control knob comes standard and allows for manual air volume adjustment. An optional magnehelic gauge is available to assist in monitoring the HEPA filter’s saturation level.

sas powder containment hoods


On our YouTube channel we have a video demonstrating one of our Ductless Containment Hoods for a pharmaceutical capsule filling process.

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Our line of pharmaceutical powder containment hoods are not intended for sterile compounding applications.

Contact Sentry Air

If your non-sterile compounding practice could benefit from powder containment, give Sentry Air Systems a call. One of our technical applications specialists will work with you to determine the best solution. Call 800.799.4609, email sales@sentryair.com or fill out the comment form below.