Ingestion is the process by which hazardous substances enter the body through the mouth and digestive system, usually by swallowing contaminated food, drink, or particles transferred from hands or objects.
Explanation
In occupational health and safety, ingestion is recognized as one of the four primary routes of entry for hazardous substances, alongside inhalation, absorption, and injection. Ingestion is often considered a less common primary route of exposure in the workplace compared to inhalation or skin contact, but it is a significant and potentially serious one. It is a significant risk in industries involving toxic metals like lead or cadmium, or where chemical residues are common.
Once a chemical is swallowed, it travels to the stomach and intestines, where it can be absorbed into the bloodstream. This can lead to systemic health effects, poisoning, gastrointestinal irritation, or long-term systemic effects, damage to internal organs, such as the liver and kidneys.
In occupational safety, ingestion is an accidental route of exposure that happens when workers unknowingly transfer chemicals from their hands to their mouths, rather than someone deliberately drinking a chemical.
Key factors in the workplace that increase the risk of ingestion include:
- Poor Personal Hygiene: This is the leading cause. Failing to wash hands before eating, drinking, smoking, or applying cosmetics after handling hazardous materials can lead to the transfer of chemicals from the hands to the mouth.
- Contaminated Food and Drink: Storing food or beverages in areas where chemicals are used, or using chemical containers (like beakers or flasks) for drinking, can lead to accidental ingestion.
- Hand-to-Mouth Contact: Activities like nail-biting, chewing on pens, or wiping the face with contaminated gloves or hands.
- Swallowing Inhaled Particles: Some dusts or aerosols inhaled through the nose can be carried by mucus into the throat and then swallowed.
Examples
A classic example is a worker at a battery recycling plant who is exposed to lead dust.
The worker handles lead-containing materials all morning, and fine lead dust settles on their hands and clothing. At lunchtime, they don’t wash their hands thoroughly before eating their sandwich. The lead dust is transferred from their hands to the food and is then ingested. Even though the amount swallowed each day is tiny, the lead accumulates in their body over months and years, eventually causing severe health problems like neurological damage, kidney disease, and reproductive issues.
Other Examples:
- Pesticides: Agricultural workers may ingest pesticide residues if food or drinks are consumed in the field without prior handwashing.
- Asbestos fibers: Contaminated clothing or hands may transfer microscopic asbestos particles to food, leading to ingestion and long-term health risks.
- Chemical mistaken for water: A worker accidentally drinks butanol, a colorless chemical stored in a water bottle, because it looked like water. Unfortunately, the chemical had been improperly stored, and the container was not removed from the workplace, leading to a serious ingestion hazard.
Another Example:
A mechanic is working on an engine, using a parts-cleaning solvent containing a hazardous chemical like toluene to degrease components.
After finishing the task, the mechanic wipes his hands on a rag but does not wash them thoroughly with soap and water. He then goes on his lunch break and immediately eats a sandwich.
Traces of the toluene solvent remain on his hands and under his fingernails. When he handles his food, the chemical transfers to the sandwich. When he eats the sandwich, he ingests the toluene.
Once ingested, the toluene can be absorbed into his bloodstream, potentially causing symptoms like dizziness, nausea, headaches, or, with repeated exposure, more serious damage to the liver, kidneys, or nervous system.
« Back to Glossary Index