The single most demanding building-systems problem in a cancer center's pharmacy is containing the antineoplastic (chemotherapy) drugs it compounds. USP General Chapter <800> Hazardous Drugs — Handling in Healthcare Settings governs how those rooms are built, pressured, and exhausted, and it is the design driver that distinguishes an oncology pharmacy from any other hospital pharmacy.
USP <800> sets the facility envelope for compounding hazardous drugs
USP <800> is the controlling standard for receiving, storing, compounding, and disposing of hazardous drugs (HDs) across the healthcare enterprise — not just the cleanroom. It works in tandem with USP <797> (sterile compounding) and USP <795> (nonsterile compounding): <797>/<795> establish the cleanliness and sterility requirements, while <800> overlays the containment requirements specific to drugs on the NIOSH Hazardous Drug List. For a designer, <800> is what makes the rooms negative, exhausted, and segregated.
A few framing points that shape every design decision:
- The NIOSH list defines scope. Whether a room needs <800> containment depends on which drugs on the NIOSH list are handled and in what form (antineoplastics requiring full containment vs. certain non-antineoplastic or final-dosage-form-only handling that an Assessment of Risk may scope down). The pharmacy's Assessment of Risk (AoR) documents this and is a programming input the design team must obtain early.
- <800> is enforceable. Although USP is a compendial standard, state boards of pharmacy and accreditors (TJC, DNV) adopt and survey to it, so for practical purposes it carries the weight of code for the AHJ. Treat it as mandatory, not advisory.
- It governs the whole HD path. Receiving/unpacking, storage, compounding (sterile and nonsterile), administration support, and waste — each link has containment implications, so the pharmacy suite must be planned as a connected sequence, not a single cleanroom.
Hazardous drugs are compounded inside primary engineering controls
The drug is never open to the room air of even a negative room. It is manipulated inside a Primary Engineering Control (PEC) — a ventilated cabinet that captures contaminant at the point of generation and exhausts it. The two PEC families an oncology pharmacy uses:
- Class II Biological Safety Cabinet (BSC), Type B2 (preferred) or B1 — for sterile HD compounding. A C-PEC for sterile HD work must be externally vented; total-exhaust Type B2 cabinets (no recirculation back to the room) are the cleanest fit for HD work, though B1 cabinets are also used. (Class II Type A2 cabinets recirculate and are generally reserved for non-HD or limited applications.)
- Compounding Aseptic Containment Isolator (CACI) — a closed, glove-box-style isolator for sterile HD compounding, also externally vented.
- Containment Ventilated Enclosure (CVE) or Class I BSC / CACI equivalent — for nonsterile HD compounding (e.g., crushing tablets, repackaging), providing capture exhaust without the sterility requirements.
The PEC sits inside a room — the Secondary Engineering Control (SEC) — and the combination of the two, plus containment practices and PPE, is what <800> calls containment. Critically, a PEC alone is not sufficient for antineoplastic sterile compounding: it must be housed in a properly pressurized, exhausted, ISO-classified room.
The room (SEC) must be negative pressure, externally exhausted, and ISO-classified
The Secondary Engineering Control is the buffer room (and its anteroom) that contains the PEC. For HD sterile compounding the SEC must simultaneously satisfy <800> containment and <797> cleanliness:
| Parameter |
Typical requirement (rule-of-thumb) |
| Room pressurization |
Negative relative to adjacent spaces — commonly cited around −0.01 to −0.03 in. w.c. |
| Air changes per hour (ACH) |
≥ 30 ACH for the ISO 7 HD buffer room (the PEC's own HEPA-filtered airflow contributes to total) |
| Air cleanliness |
ISO Class 7 buffer room; ISO Class 7 (or better) anteroom serving negative-pressure HD areas |
| Exhaust |
100% exhausted to the outside — no recirculation of HD-area air back into the building |
| HD storage |
HDs requiring refrigeration stored in a dedicated refrigerator in a negative-pressure room, with ≥ 12 ACH; the negative-pressure storage room is also externally exhausted |
Key design consequences:
- Negative pressure is the inversion of the usual cleanroom instinct. A standard <797> non-HD sterile cleanroom is positive. The HD room is negative so contaminated air cannot escape into adjacent spaces. That trade — sterility wants positive, containment wants negative — is resolved by making the room negative but keeping the PEC's first-air ISO 5 critical zone protected, and by using the anteroom as the pressure-and-cleanliness buffer.
- The anteroom is the airlock. The pressure cascade typically steps from the cleaner anteroom into the negative HD buffer room, with hand-off/pass-through and gowning sequencing that maintains the cascade. Door interlocks, low-leakage construction, and properly sized transfer of air all matter.
- Continuous monitoring and alarms. Pressure differentials are monitored with a continuous reading device and audible/visible alarms, because loss of negative pressure is a containment failure, not just a comfort issue. This is a coordination item with the BAS and with NFPA-99-driven alarm strategy.