Under the Microscope: Formaldehyde Inhalation Exposure in NHS Pathology Departments

ObjectivesThe United States Environmental Protection Agency has determined that formaldehyde presents an "unreasonable risk of injury to human health." Occupational inhalation exposure is associated with short- and long-term damage to the respiratory, female reproductive, and nervous systems, and is also carcinogenic. The European Union (EU) has recently introduced formaldehyde workplace exposure limits (WELs) that are lower (long-term: 0.3ppm; short-term: 0.6ppm) than those currently applied in the United Kingdom (UK) (long-term: 2ppm; short-term: 2ppm). UK regulation additionally requires exposure to carcinogens to be reduced to as low as is reasonably practicable. We evaluated formaldehyde airborne concentrations in National Health Service (NHS) cell pathology departments to assess the adequacy of exposure controls. MethodsUsing the Freedom of Information Act (2000), we requested 12 months (2024-2025) of formaldehyde airborne monitoring data collected by cell pathology departments across n=122 NHS Trusts in England (n=102), Scotland (n=10), Wales (n=6), and Northern Ireland (n=4). Results were evaluated empirically and using EN 689:2018 statistical methods to assess exposure variability, estimate upper-bound concentrations, and determine the likelihood of adequate exposure control when benchmarked against EU WELs. ResultsA total of 1,715,516 formaldehyde airborne monitoring results were disclosed by n=117 cell pathology departments. Monitoring was infrequent, with 73% of sites measuring formaldehyde airborne concentrations once weekly or less. EU long-term WELs were exceeded regularly at 70% of sites (95th percentile >0.3 ppm), and EU short-term WELs were exceeded regularly at 43% of sites (95th percentile >0.6 ppm). The 95th percentile upper tolerance limit (UTL95,70) exceeded the EU short-term WEL at 68% of sites. Only 11% and 17% of departments demonstrated frequent (once daily or more) formaldehyde airborne monitoring with 95th percentiles below the EU long- and short-term WELs, respectively. ConclusionsFormaldehyde exposure is infrequently monitored and inadequately controlled in NHS cell pathology departments. What is already knownA substantial body of occupational exposure data shows that formaldehyde inhalation is associated with myriad short- and long-term deleterious health effects on the respiratory, female reproductive, and nervous systems. It is also a human carcinogen. Pathology departments are amongst the riskiest occupational environments for formaldehyde inhalation exposure and therefore require a high standard of governance and infrastructure to adequately protect staff. What this study addsWe show that formaldehyde airborne concentrations in most NHS cell pathology departments are monitored infrequently and regularly exceed EU WELs. Our data raises concern for the health of thousands of NHS employees working in these environments. How this study might affect research, practice, or policyUrgent national regulatory intervention is now warranted to improve the occupational hygiene of NHS cell pathology departments. This will require a combination of upgraded infrastructure, more regular personal exposure monitoring, better employee education on basic lab practice and occupational health risks, improved access to appropriate personal protective equipment, management accountability for occupational health, and external oversight by the Health and Safety Executive.