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The Top 4 Pathways for Chemical Exposure

By Adrian Bartha
Published: December 9, 2013 | Last updated: July 15, 2022 09:30:46
Key Takeaways

To protect workers from hazardous substances, we first have to identify the type of exposure risk they face.

Caption: Worker Transferring Hazardous Material to Another Container Source: DSCimage / iStock

Some chemicals have harmful effects that take place at the surface level. Corrosive substances leave burns and wounds. Irritants cause redness, itchiness, and discomfort.

Toxic chemicals, however, also have effects that run deeper. The acute and chronic health problems that come from chemical exposure result from the hazardous substances entering the body through one of four primary pathways:

  • Inhalation (breathing it in)
  • Ingestion (swallowing it)
  • Opthalmic absorption (through the eyes)
  • Demal absorption (through the skin)

From those access points, the substance can enter the bloodstream and reach the lungs, liver, kidneys, and other internal organs.


In this article, we'll take a look at these four pathways for exposure and how to keep workers safe from each of them.

Chemical Forms

Chemicals can take various forms, including:

  • Solids, including dusts and fibers
  • Liquids
  • Gases
  • Vapors, fumes, and mists

The form of a chemical is an important consideraiton, since it will determine how the substance can get into the body. It is important to note, however, that the same chemical can be found in different forms and undergo changes to its form, such as a liquid turning to vapor.

Acute vs. Chronic Effects

When a toxic chemical enters the body, its effects can be acute or chronic.

Acute effects are evident either immediately or shortly after the exposure takes place. They can range from minor symptoms like irritation of the throat to more serious ones like impaired vision.

Chronic effects, on the other hand, may only manifest after repeat exposure or over a longer span of time. Some may only become evident even years after the exposure has ceased, as is the case with some lung diseases and occupational cancers.

(Learn more about Toxic Heavy Metals and Occupational Cancer Risks)

Exposure Through Inhalation

Chemicals can be inhaled in the form of gases, vapors, mists, dust, fumes, and smoke. After going through the nose, these substances enter the lungs, where they are absorbed into the bloodstream and distributed throughout the body. If the substance is toxic, symptoms of exposure can include difficulty breathing, dizziness, or loss of consciousness.

If fumes are present in the area, the first step is to move the affected individual away from the site in order to prevent further inhalation. If possible, move to an outdoor space or one that is well ventillated.


Workers who might face inhalation hazards should be provided with respirators that provide sufficient protection. The chemical product's safety data sheet can guide your selection.

(Learn more in Everything You Need to Know About Safety Data Sheets)

Exposure Through Ingestion

Since workers have no interest in tasting any of the the materials they work with, most ingestion of toxic chemicals happens indirectly. It results from bringing fingers to the mouth after handling the substance, or from drink containers or food that has become contaminated.

When ingestion takes place, contacting a poison control center is a good way to get further guidance. In most cases, however, a worker who has ingested harmful chemicals should be sent to the hospital.

Unfortunately, not much can be done at the scene. Helping the affected worker may require the use of a nasogastric tube, induced vomiting, or other procedures that should be handled by a trained medical professional.

Preventing chemical ingestion is primarily a matter of establishing work processes that prevent cross-contamination. Food and drinks should only be allowed in approved areas. Workers should be trained not only to use hand protection when dealing with chemicals but how to safely remove them to reduce the risk of exposure.

Exposure Through the Eyes

While most workers are aware of the chronic health risks that come from ingesting and inhaling chemical products, many do not know that exposure can also take place through the eyes.

Chemicals can come in contact with the eyes through vapors, liquid splashes, or transfer from the finger to the eyes. Once absorbed, it can quickly enter the bloodstream.

Using eyewash to flush the chemical from the eye might be sufficient, but the exact treatment needed will depend on the chemical involved.

In some cases, simple safety glasses will be sufficient to protect the eyes. However, chemical forms such as vapors will require eye protection with covered vents or that provide a complete seal around the eyes.

(Learn more in Goggles vs. Glasses: Which Is the Right Safety Eyewear for Your Job?)

Exposure Through the Skin

While the skin is meant to protect the body from the entry of bacteria and other potential invaders, it is nevertheless porous and can absorb chemicals and other harmful substances. In fact, dermal absorption is the second most common route by which toxic substances enter the body.

Skin that has been exposed to a harmful substance should be washed immediately to prevent absorption or at least prevent further absorption. If the worker displays symptoms of exposure, they should be taken to the hospital.

To keep hazardous materials from coming in contact with the skin, workers should wear protective clothing that provides sufficient cover. Gowns, gloves, and protective sleeves may be required as well. Disposable coveralls should be disposed of safely and not be re-used.

(Learn about 6 Jobs That Call for Disposable Clothing)

Preventing Chemical Exposure

While there are various first aid procedures that can minimize the harm caused by harmful chemicals, the most important step any employer can take is to prevent the exposure from happening in the first place.

If possible, eliminate the hazard entirely by eliminating the use of the chemical product. If the chemical is essential for the work, look into the possibility of substituting it for one with less harmful effects.

Engineering controls, such as improved ventilation and installing barriers between workers and the chemicals, are also effective. As are changes in work practices that could minimize contact with harmful substances.

Finally, anyone working with chemicals should be equipped with adequate presonal protective equipment (PPE) and trained in its proper use.


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Written by Adrian Bartha | Chief Executive Officer

Profile Picture of Adrian Bartha
Adrian Bartha is the CEO of eCompliance, which he joined in 2012 after experiencing first-hand how a workplace incident affected a power and utilities company which he led as a member of the Board of Directors. Previously, Adrian was an investment professional for a $5 billion dollar private equity firm investing in energy, construction, and transportation infrastructure companies across North America. When Adrian is out of the office, he can be found riding his futuristic motorcycle and wearing his RoboCop helmet.
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