A survey of exposure to and urinary excretion of vanadium and response to heat stress in boiler cleaners working in Scotland

Between July and November 1991, 24/31 boiler cleaners working on six oil‐fired boilers of varying sizes provided periodic samples of urine which was analysed for its vanadium content. Eight of these men also had their heart rate and body temperature monitored The dust, its vanadium and nickel content and thermal aspects of the workplace environment were assessed using standard occupational hygiene techniques. Urinary excretion of vanadium depended on length of exposure, method of cleaning and vanadium content of the ash. Thus high amounts (270.1 μg l^‐1, median 77.4 μg l^‐1) were observed during ‘dry’ cleaning, when eight hour time weighted average dust and vanadium levels of up to 357 and 88.7 mg m^‐3 respectively were found when the ash had a vanadium content of 15%. Nickel comprised 4.64%. Although ‘wet’ methods produced much lower levels, extremely high short term exposures could still occur ‐ 210 mg m^‐3 and 15.2 mg m^‐3 for dust and vanadium during a 10 min period ‐ emphasising the need for adequate personal protective equipment. Even under conditions of heat stress, core temperatures always stayed within safe limits, and maximum predicted heart rates were rarely exceeded ‐ the greatest excursion in any of those monitored was for only 2.8% of the working day.