Scenario 3: Routes of exposure by Then

Case study

thenyoonyee — 2023-03-20 04:57:17 UTC

Sara works in a laboratory that develops new pharmaceutical products. Her job involves handling various chemicals and drugs, as well as performing experiments and tests to evaluate their effectiveness and safety. One day, Sara is working with a new drug and accidentally inhales some of the fumes generated during the experiment. The drug is known to be toxic when inhaled, and Sara starts to feel lightheaded and dizzy.

Key discussion points

thenyoonyee — 2023-03-20 05:04:16 UTC

1. The 4 main routes of exposure of hazardous substances

2. The possible routes of exposure in this case

3. The PPEs that are suitable for Sara to prevent this incident

2026-03-30 02:44:48 UTC

1. Eye and face protection

Safety goggles or full-face shield to prevent irritation from vapors and to prevent chemicals to get into eyes from spillage

2. Gloves

Chemical-resistant gloves (nitrile or neoprene) to prevent skin contact with hazardous chemicals which might cause irritations.

3. Protective clothing and foot coverings

Wearing lab coat to avoid contamination.

However in this case, a specific mask is recommended to be worn by Sara

2026-03-30 02:48:38 UTC

2026-03-30 02:52:58 UTC

Elastomeric half face respirators are reusable, tight-fitting masks made of flexible silicone or rubber with replaceable filters, providing, when properly fitted, a high level of protection against particulates, gases, and vapors.

The standard advice for filter replacement is 40 hours of use or 30 days, but if Sara starts noticing strange odors, or if she faces difficulty breathing, she should replace the filters immediately

Dermal Absorption

2026-03-30 03:01:53 UTC

Dermal absorption happens when chemicals pass through the skin and enter the bloodstream

It will happen when:

Chemical spills on skin
Handling chemicals without proper gloves
Contact with contaminated surfaces
Wearing damages or permeable protective equipment

Chemicals will penetrate the outer skin layer (epidermis) and enter deeper layers to reach the blood vessels, then spread throughout the body via circulation

Effects to body: skin irritations (redness, itchy, burning sensations), systemic toxicity (affecting internal organs)

Prevention:

Wear appropriate gloves, lab coat and PPE
Clean spills immediately
Avoid direct contact with chemicals

Ingestion

2026-03-30 03:02:31 UTC

Ingestion occurs when hazardous substances enter the body through the mouth and are swallowed into the digestive system

It will happen when:

Eating and drinking in the laboratory
Touching food with contaminated hands or gloves
Poor hygiene (not washing hands after handling chemicals)

Chemicals will enter the stomach and intestine, and absorbed into the bloodstream. It will then transported to organs like the liver, and it may cause damage.

Effects to body: nausea, vomiting, poisoning, organ damage

Prevention:

Never eat and drink in the laboratory
Wash hands after handling chemicals and after experiment
Avoid touching your face

Ingestion

2026-03-30 03:02:55 UTC

The chemicals entry into the body from the mouth, pass through the digest system and finally go into the bloodstream.
Some are easily absorbed in the stomach and some may become more toxic after metabolism.
The chemicals might contaminated on Sara's hand. When she touch her face and mouth, she may ingest the chemicals.
Sara may also not have followed to the lab safety guidelines and eat or drink something in the lab. Then she ingest the chemicals when using her hand which has chemical contaminated.
Eventually, if the food is put near the work area, the chemical fume will also settle on the food. Sara will accidental ingest the chemicals through this way.
Sara may also not wear the PPE and the fume of chemical contaminated on her skin and clothes. She bring the chemicals adhere to the clothes back to her house.
Even if she was wearing gloves, he may use the gloves to touch her phones, pens or door handling. She touch her phones, pens or door handling after take off the gloves.
Then, she not washing her hand and touch her face then she ingest indirectly.

2026-03-30 03:03:54 UTC

Inhalation (most relevant)
-Sara may accidentally breathe in toxic fumes produced during the experiment.
-The toxic will enter her respiratory system and passes rapidly into the bloodstream, causing symptoms like dizziness and lightheadedness.
-Exposure may occur in the form of gases, vapours, fumes or dust.
Dermal (Skin) Absorption
- This kind of exposure may occur if there are spills or direct contact occur during handling.
- Some chemicals can penetrate the skin easily then damaged the skin.
- The risk increase if the skin has cuts or prolonged exposure.
- This highlights the importance of personal protective equipment (PPE) such as gloves and lab coats.

Injection

2026-03-30 03:13:29 UTC

Injection is a route of exposure where hazardous substances enter the body directly through the skin via an opening, instead of passing through the air or digestive system.

substances entering through cuts, wounds, or punctures (e.g., needles)

It will happen when:

-Cuts from broken glass contaminated with chemicals

-Handling sharps improperly

-Accidentally punctures from sharp instruments

Substances bypass the skin barriers

Directly enter the bloodstream or tissue

Spread quickly throughout the body

Effects to body:

-immediately exposure to toxic substances

-risk of infection

-local injury (pain swelling)

Prevention:

-wear protection gloves

-properly dispose of needles in sharp containers

-handle sharp objects carefully

Inhalation

2026-03-30 03:13:53 UTC

breathing in gases，vapors，fumes，or dust

Inhalation is one of the most common and dangerous routes of exposure in workplaces like laboratories.

It happens when:

-harmful substances in the air are breathed into the lungs

-working without proper ventilation (eg.no fumes hood)

Chemical will enters the lungs and quickly absorbs into bloodstream than distributed rapidly to organs like brain

Effects to body: dizziness ,headaches,breathing difficulties

To prevent:

-use proper safety measures

-wearing appropriate respiratory protection

2026-03-30 03:32:06 UTC