Injection is the process by which hazardous substances enter the body’s tissues or bloodstream through a puncture or break in the skin, often caused by sharp objects, high-pressure equipment, or animal/insect bites.
Explanation
In occupational health and safety, Injection is one of the four main routes of entry for harmful substances in the workplace, along with inhalation, ingestion, and absorption. Caused by contaminated sharp objects like needles or nails, or from high-pressure equipment, this route can introduce hazardous substances deep into the tissue, the bloodstream, or even bone, making them difficult to remove and capable of causing severe damage far from the initial entry point.
This makes it a particularly dangerous route of exposure for several reasons:
- The substance can enter the bloodstream almost immediately, leading to a very fast systemic effect.
- A significant dose with high concentration can be delivered to a localized area.
- In addition to chemical hazards, the puncture wound itself carries a high risk of bacterial infection or the transmission of bloodborne pathogens.
Injection exposures can occur in several ways:
- Needle sticks or cuts from contaminated sharp objects.
- High-pressure injection injuries occur when paint, grease, or hydraulic fluids are forcefully injected under the skin. These injuries are most frequently associated with equipment that uses high-pressure fluid systems, such as:
- Grease guns
- High-pressure paint or solvent sprayers
- Hydraulic systems (e.g., fluid from a ruptured hydraulic line)
- Diesel fuel injection systems
- Water-jet cutters and high-pressure water cleaners
- Animal or insect bites/stings, which may transmit toxins, allergens, or infectious agents.
- These types of injuries are particularly dangerous because they may not appear severe externally but can cause serious infection, tissue damage, or systemic poisoning.
Injection is a critical occupational exposure route where hazardous substances bypass natural skin barriers and directly enter the body.
Examples
A mechanic is using a high-pressure grease gun to lubricate a fitting on a large piece of heavy machinery. The fitting is clogged. While trying to force grease into it, the mechanic uses their free hand to steady the hose near the fitting.
Suddenly, the clog clears. A stream of grease is ejected from a pinhole leak in the hose they are holding. The high-pressure stream (which can exceed 10,000 psi) instantly penetrates the mechanic’s glove and skin at the base of their index finger.
The entry wound is tiny, perhaps just a small dot. The mechanic might feel a stinging sensation but initially dismisses it as minor.
The grease has been injected deep into the palm, tracking along the tendon sheaths and into the carpal tunnel. Within hours, the hand became extremely painful, swollen, and red as the foreign material triggered an intense inflammatory response, and the grease compromised blood flow to the fingers.
This is a medical emergency. The mechanic must stop work immediately, inform their supervisor, and be transported to a hospital emergency room without delay. The supervisor must report the incident as required by local OHS regulations. The equipment involved should be tagged out and taken out of service for inspection and repair to prevent a recurrence. This incident would also trigger a workplace investigation to determine why safe work procedures (e.g., using injection-resistant gloves, verifying equipment integrity, never using hands to check for leaks) were not followed.
Other Examples:
- Healthcare setting: A nurse or doctor administering medication might accidentally prick their finger with the used needle after giving a patient an injection. If the patient has a bloodborne disease like Hepatitis B, Hepatitis C, or HIV, the virus can be transmitted directly into the healthcare worker’s bloodstream through this small puncture wound. This single event can lead to a life-threatening illness, highlighting the severe risk associated with injection as a route of exposure.
- Agriculture: A worker is bitten by an insect carrying a disease (e.g., mosquitoes transmitting malaria).