Drug compounding and preparation carry the highest risk of exposure to hazardous drugs in healthcare settings. Specifically, reconstituting powdered drugs, transferring liquid between vials and syringes, and priming IV lines create the most opportunities for aerosolization, splashing, and skin contact. About 8 million U.S. healthcare workers face potential exposure, and the risk extends well beyond pharmacists and nurses to include janitorial staff, shipping personnel, and anyone who touches contaminated surfaces.
Why Preparation Is the Highest-Risk Activity
Every time a hazardous drug moves from one container to another, small amounts can escape into the air or onto surfaces. Piercing a vial stopper with a needle, withdrawing fluid into a syringe, breaking open an ampule, expelling air from a filled syringe, and injecting drug into an IV bag all generate tiny droplets or aerosols. Priming an IV line (running drug-containing fluid through tubing to push out air) is another well-documented source of exposure. These aren’t dramatic spills. They’re routine, repeated manipulations that release microscopic amounts of drug dozens of times per shift.
Compounding pharmacists and pharmacy technicians face the most concentrated risk because they perform these manipulations repeatedly in sequence. A single preparation might involve piercing a vial, drawing fluid, injecting it into an IV bag, and priming the line, each step creating another chance for drug to escape.
Administration and Other High-Risk Tasks
Nurses who administer hazardous drugs face the second-highest tier of risk. Spiking an IV bag, connecting and disconnecting tubing, and managing accidental disconnections in a drug delivery system all allow liquid to leak or splash onto skin and work surfaces. Administering a drug through an aerosol nebulizer is particularly concerning because it produces measurable drug concentrations in the breathing zone of the worker delivering the treatment.
Less obvious but significant sources of exposure include crushing or splitting hazardous drug tablets, which generates airborne dust containing active drug. Placing oral solid forms of hazardous drugs in automated pill-counting machines produces “pill dust” that settles across the work area. Spill cleanup, disposal of contaminated waste, and handling soiled linens or patient excreta (which can contain active drug metabolites) also create exposure risk for environmental services workers who may not realize they’re handling hazardous material.
How Hazardous Drugs Enter Your Body
There are three main routes: skin absorption, inhalation, and accidental ingestion (usually from touching contaminated surfaces and then touching your mouth or food). For many hazardous drugs, skin contact is actually a more significant route of exposure than breathing, particularly for chemicals that aren’t volatile. These drugs settle on countertops, IV poles, floors, and door handles, then remain there for extended periods. Anyone who touches those surfaces without gloves absorbs small amounts through the skin.
Inhalation becomes the dominant concern during activities that generate aerosols or dust, like compounding, nebulizer treatments, or crushing tablets. The combination of both routes over weeks and months of regular work creates a cumulative dose that can produce measurable biological effects.
Surface Contamination Is Widespread
Researchers have repeatedly measured drug residue on surfaces throughout pharmacies and oncology units, even in areas where preparation doesn’t take place. A long-term monitoring study spanning 48 hospitals and pharmacies over 13 years, involving more than 9,000 analyses, found contamination persistent enough to require formal guidance values. The recommended threshold for acceptable surface contamination in areas where hazardous drugs are handled is 100 picograms per square centimeter, an extraordinarily small amount that reflects just how potent these drugs are and how seriously even trace residue is treated.
This contamination doesn’t stay in the pharmacy. Drug residue has been found on doorknobs, phones, chairs, and other surfaces in patient care areas, meaning workers who never directly handle the drug can still absorb it through their skin during a normal shift.
Health Consequences of Chronic Exposure
The most extensively studied hazardous drugs are antineoplastic agents (cancer chemotherapy drugs), many of which are designed to damage DNA. For healthcare workers with chronic low-level exposure, the consequences show up most clearly in reproductive health. A meta-analysis of multiple studies found that exposed workers had a 46% higher risk of miscarriage compared to unexposed workers. Individual studies have reported even steeper numbers. One found nearly double the odds of miscarriage among exposed nurses.
Beyond pregnancy loss, occupational exposure to antineoplastic drugs has been linked to congenital malformations, reduced fertility in both men and women, damage to ovarian follicles, and decreased ovarian volume. Researchers have also documented significant increases in markers of genetic damage (chromosomal abnormalities and DNA mutations) in exposed healthcare workers compared to control groups. These aren’t effects from a single accidental spill. They emerge from the kind of low-grade, repeated exposure that happens when protective measures are inadequate.
Who Is Most at Risk
Compounding pharmacists and pharmacy technicians top the list because of frequency and intensity of drug manipulation. Oncology nurses rank close behind. But the full list of at-risk workers is longer than most people expect: environmental services staff who clean treatment rooms, laundry workers who handle contaminated bedding, shipping and receiving personnel who unpack drug shipments, and transport staff who move waste containers. USP General Chapter 800, the current national standard for hazardous drug handling, applies to all personnel who receive, prepare, administer, transport, or otherwise come in contact with these drugs, in any healthcare environment.
How Exposure Is Reduced
The most effective single intervention is using closed-system transfer devices (CSTDs) during drug preparation. These sealed mechanisms prevent drug vapor and liquid from escaping during transfers between vials, syringes, and IV bags. A study across 30 U.S. hospital pharmacies found that implementing CSTDs reduced surface contamination with cyclophosphamide (a common chemotherapy drug) by 86%, with some facilities achieving reductions of 95%. The median contamination dropped from 0.22 to 0.03 nanograms per square centimeter.
CSTDs work best as part of a layered approach. USP 800 requires a combination of engineering controls (ventilated cabinets, negative-pressure rooms), proper personal protective equipment (chemotherapy-rated gloves, gowns, and in some cases respirators), standardized decontamination and cleaning procedures, spill control protocols, and thorough documentation. The standard applies not just to pharmacies but to every point in the drug’s journey through a facility, from the loading dock to the patient’s bedside to the waste bin.
For workers in these environments, the practical takeaway is straightforward: the moment a hazardous drug is opened, transferred, or touched, exposure is possible. The highest risk concentrates where drugs are physically manipulated, but residue spreads far beyond those areas. Protective equipment and closed-system devices dramatically reduce that risk when used consistently.