NIOSH researchers conducted a field survey at Veterinary Hospital F in August 2018. The purpose of the site visit was to identify and evaluate hazardous drug engineering controls as well as to sample for potential surface contamination at the hospital. NIOSH researchers also observed and interacted with the hospital's veterinarians and staff to obtain information about the hazardous drug work practices, daily activities, and oncology treatment processes. A TSI Accubalance Plus Air Capture Hood Model 8373 was used to measure mechanically generated supply and exhaust airflows in the pharmacy's main room and cleanroom areas. Air measurements were taken using the instrument's backpressure compensation to ensure accurate readings. The pharmacy area had more supply air (0.52 m3/s or 1098 cfm) than was mechanically exhausted (0.16 m3/s or 329 cfm) which aligned with the positive pressure observation earlier in the qualitative test with the Wizard Stick handheld smoke generator. The positive pressure non-hazardous drug sterile compounding cleanroom calculated air changes per hour (ACH) was 104, thus exceeding the minimum ACH requirements [USP 2019]. The anteroom's calculated ACH was 63, also exceeding the minimum ACH requirements [USP 2019]. The negative pressure hazardous drug sterile compounding cleanroom calculated ACH was 69, also exceeding the minimum ACH requirements [USP 2019]. The pressure differential from the anteroom to the general pharmacy area was 0.07 inches of water, from the anteroom to the negative pressure hazardous drug sterile compounding cleanroom was 0.04 inches of water; and from the anteroom to the positive pressure non-hazardous drug sterile compounding cleanroom was 0.03 inches of water. Recently-conducted certification records indicated the negative pressure hazardous drug cleanroom supply was 0.20 m3/s (434 cfm) and it had a negative pressure of -0.017 inches of water, which meets the USP <800> requirement of -0.01 to -0.03 inches of water [USP 2019]. During the NIOSH site visit, the Magnehelic pressure differential gauge read -0.04 inches of water. The room remained very negative despite on-site maintenance staff efforts to correct the problem. Since both biological safety cabinets (BSCs), one-each within the positive pressure and negative pressure cleanrooms, were recently certified prior to the NIOSH visit, these were not quantitatively evaluated during the field survey. The presence of potential surface contamination was evaluated with wipe samples. These were collected in areas where the staff handled chemotherapy drugs, such as the oncology department. Wipe samples were also collected in less obvious places (i.e., telephone, door handles) to determine if current workplace safety practices at the hospital were adequate to prevent inadvertent contamination of these surfaces. In some cases, a single sample could be evaluated for more than one analyte simultaneously. Vinblastine and cyclophosphamide were the drugs handled during the NIOSH visit. NIOSH staff did not see chemotherapy administration to patients during the visit. Sample results revealed that 1 out of 9 wipe samples submitted for carboplatin was positive (6.75 ng/sample). The 2 samples submitted for vinblastine were non-detectable (ND). The ND determination means that contamination was either not present, or was present at levels below the detectable limit of the analytical method. Two of 19 samples submitted were positive for cyclophosphamide (3.6 ng/sample) and doxorubicin (1.0 ng/sample) while simultaneously being ND for vincristine, epirubicin, and methotrexate. The doxorubicin wipe sample was between the limit of detection (LOD) and limit of quantification (LOQ). Five out of 5 wipe samples submitted for N-methyldiethanolamine (MDEA) were positive (5.2 to 48.6 ng). All of the 5 wipe samples submitted for toceranib, chlorambucil, and lomustine were ND. MDEA was monitored as a potential stable marker for the highly unstable antineoplastic drug mustargen as explained in the text. Although some of the wipe sample analytical results were ND, there is no safe level of exposure when handling hazardous drugs. The carboplatin, cyclophosphamide, doxorubicin, and MDEA presence serves as a reminder that hazardous drug contamination can sometimes linger despite cleaning efforts. Therefore, it is important to continue to use engineering controls (e.g., biological safety cabinets), supplementary controls (e.g., closed system drug-transfer devices), protective work practices (e.g., surface cleaning after every oncology patient, regardless of whether I.V. chemotherapy was administered), and personal protective equipment (e.g., gloves and gowns rated for chemotherapy protection, respirators, shoe covers, eye protection) to reduce unintentional exposures to the staff or pet owners.