No abstract

Formaldehyde has carcinogenic properties. It is associated with nasopharyngeal cancer and causes irritation of the eyes, nose, throat, and respiratory system. Formaldehyde exposure is a significant health concern for those participating in the gross anatomy laboratory, but no learning method can substitute cadaver dissection. We performed a formaldehyde level study in 2018, which found that most of the breathing zone (S-level) and environment (R-level) formaldehyde levels during laboratory sessions at the Faculty of Medicine Siriraj Hospital exceeded international ceiling standards. In the academic year 2019, we adapted the engineering rationale of the NIOSH hierarchy of controls to facilitate formaldehyde clearance by opening the dissection table covers and increasing the area per dissection table, then measured formaldehyde ceiling levels by formaldehyde detector tube with a gas-piston hand pump during (1) body wall, (2) upper limb, (3) head-neck, (4) thorax, (5) spinal cord removal, (6) lower limb, (7) abdomen, and (8) organs of special senses dissection sessions and comparing the results with the 2018 study. The perineum region data were excluded from analyses due to the laboratory closure in 2019 from the COVID-19 outbreak. There were statistically significant differences between the 2018 and 2019 S-levels ( p < 0.001) and R-levels ( p < 0.001). The mean S-level decreased by 64.18% from 1.34 ± 0.71 to 0.48 ± 0.26 ppm, and the mean R-level decreased by 70.18% from 0.57 ± 0.27 to 0.17 ± 0.09 ppm. The highest formaldehyde level in 2019 was the S-level in the body wall region (1.04 ± 0.3 ppm), followed by the S-level in the abdomen region (0.56 ± 0.08 ppm) and the spinal cord removal region (0.51 ± 0.29 ppm). All 2019 formaldehyde levels passed the OSHA 15-min STEL standard (2 ppm). The R-level in the special sense region (0.06 ± 0.02 ppm) passed the NIOSH 15-min ceiling limit (0.1 ppm). Three levels for 2019 were very close: the R-level in the head-neck region (0.11 ± 0.08 ppm), the abdomen region (0.11 ± 0.08), the body wall region (0.14 ± 0.12 ppm), and the S-level in the special sense region (0.12 ± 0.04 ppm). In summary, extensive analysis and removal of factors impeding formaldehyde clearance can improve the general ventilation system and achieve the OSHA 15-min STEL standard. Supplementary Information The online version contains supplementary material available at 10.1007/s11356-023-26906-5.

To date, no learning method substitutes cadaver dissection, but formaldehyde exposure is a significant health concern in the gross anatomy laboratory. Our 2018 study found that most formaldehyde levels in the breathing zone (S-level) and environment (R-level) during laboratory sessions at the Faculty of Medicine of Siriraj Hospital exceed ceiling standards. In this study, we enhanced engineering control of the NIOSH hierarchy of controls by removing the intervening factors of formaldehyde clearance by increasing the area per table and opening the covers of the dissection table, then measuring the ceiling levels by formaldehyde detector tube with a gas-piston hand pump. The analyses excluded the 2018 perineum region data because of the laboratory closure from the COVID-19 outbreak in 2019. There were statistically significant differences between the 2018 and 2019 S-levels (p< 0.001) and R-levels (p<0.001). The mean S-level decreased by 64.18% from 1.34 ± 0.71 ppm to 0.48 ± 0.26 ppm, and the mean R-level decreased by 70.18% from (0.57 ± 0.27 ppm) to (0.17± 0.09 ppm). The trend of the 2019 level is similar to our 2018 study, unlike other published studies showing high formaldehyde levels in the body cavity. The highest formaldehyde level in 2019 was the S-level in the body wall region (1.04 ± 0.3 ppm), followed by the S-level in the abdominal region (0.56 ± 0.08 ppm), and the spinal cord removal region (0.51 ± 0.29 ppm). All 2019 formaldehyde levels passed the OSHA 15 min STEL standard (2 ppm). The R-level in the special sense region (0.06 ± 0.02 ppm) passed the NIOSH 15-min ceiling limit (0.1 ppm). Three 2019 levels were very close: the R-level in the head-neck region (0.11 ± 0.08 ppm), the abdominal region (0.11 ± 0.08), the body wall region (0.14 ± 0.12 ppm), and the S-level in the special sense region (0.12 ± 0.04 ppm). The lower formaldehyde level in 2019 reflects that extensive analysis of individual laboratory formaldehyde clearance defects and correcting them by applying the NIOSH hierarchy of controls is an effective measure.