Lead poisoning is a medical condition caused by excessive exposure to, and absorption of, lead. Symptoms of lead poisoning are varied and can occur in other medical conditions. Exposure to lead can lead to a range of medical problems, which is why a regime of surveillance of workers in lead industries is undertaken in Great Britain. The vast majority of individuals with blood-lead levels above the suspension level and who are suspended from lead work do not have lead poisoning, but they are removed from further exposure to lead to prevent them developing the condition.
The coverage of these statistics is limited by the extent of medical surveillance that occurs in practice, and this may not be completely aligned with what is required under the CLAW regulations. Some employers may keep workers under surveillance on a precautionary basis where exposure is not likely to be significant, whereas others may fail to implement surveillance where it is in fact required. A more detailed discussion of the basis for the statistics and their potential limitations is available on the data sources page.
The number of workers under surveillance provides a measure of the extent of potential occupational lead exposure in the national population. The following section looks at the number of workers under surveillance each year since 1996; splitting the monitored workers by gender.
The total number of workers under medical surveillance in 2009/10 increased to 7,162 persons, whereas up until then, the number has been on a downward trend since its peak of 26,700 in 1990/91. Of these 7,162 persons, 6,916 (96.6%) were males and 246 (3.4%) were females. The total number of workers under surveillance in 2008/09 was 6,831.
The total number of young people (under 18 years) under surveillance (0.1% of workforce) was 8; all of whom were male.
Recording the overall distribution of the lead workers amongst the lead based industries helps identify possible problem industrial sectors, which can then be monitored. A small number of assessments (less than 1%) had no recorded sector code; these are included for completeness under the title "Missing Sector Information".
The three industry sectors with the highest number of males under surveillance were the smelting, refining, alloying and casting industry (19.1%), the lead battery industry (18.2%) and the scrap industry (7.4%) (the ‘other processes’ category comprises many smaller industries and is therefore not used for comparison). Compared to last year the number of males under surveillance has increased in the demolition industry (from 114 [1.7%] to 328 [4.7%]) and in the scrap industry (from 301 [4.6%] to 515 [2.8%]). Numbers under surveillance have reduced in the glass making industry (from 602 [9.2%] to 166 [2.4%]) and in work with metallic lead and lead containing alloys (from 738 [11.2%] to 444 [6.4%]).
For women, the industrial breakdown shows a similar pattern to that of males with work within the smelting, refining, alloying and casting industry (17.9%), the glass making industry (17.1%) and the lead battery industry (15.9%) accounting for half of those under surveillance in the lead industry in 2009/10. Due to the small numbers involved a comparison between the current year and last year’s figures may not be reliable. However, a similar pattern to that of males was seen with the number of females under surveillance increasing in the scrap industry and decreasing in work with metallic lead and lead containing alloys. In contrast to males the number of females under surveillance in the glass making industry increased.
Since 1998/99, separate information has been collected on young people (aged under 18 years) under medical surveillance. The number of young people under medical surveillance continues to remain low with 8 individuals in total in 2009/10, a slight decline on the previous year of 22 individuals under surveillance. All young persons under surveillence were male, two worked in the smelting, refining, alloying and casting sector, a further two worked with metallic lead and lead containing alloys, one was employed in the painting of buildings and vehicles and another one in the scrap industry. A further two males worked in other smaller industries.
Workers are given blood tests to monitor the amount of lead absorbed at the workplace. High lead concentrations in the blood can reach dangerous levels if left unmonitored. If the lead concentrations in the worker’s blood reaches or passes the specified levels of concentration, the worker may be suspended from working with lead until the lead concentration reduces naturally. The figures shown here are for males with greater than 50µg/100ml and females with greater than 25µg/100ml recorded blood-lead level. All statistics are based on the highest recorded blood-lead level for each individual.
Three cut-off points are shown, representing the suspension levels under the 1980 Regulations (70µg/100ml); the suspension levels under the 1998/2002 Regulations (60µg/100ml); and the action levels under the 1998/2002 Regulations (50µg/100ml). Young males have a suspension level of 50µg/100ml and an action level of 40µg/100ml; one individual was recorded with a blood-lead level above the action limit, this individual was subsequently suspended from working with lead although his blood-lead level was below the suspension limit.
The proportion of men in the highest two categories remained broadly level between 2001/02 and 2005/06; the figures for 2006/07 to 2009/10 show a slight drop in the total level of high blood-lead measurements. In 2009/10 approximately 0.7% of male workers had blood-lead levels at or above 60µg/100ml, down from 1% in 2006/2007, 2% in 1998/99 (the first year of the lower suspension levels), and down from over 3% in 1996/97.
In 2009/10, there were 164 (2.4%) males with blood-lead levels at or above 50µg/100ml. The three industry sectors with the majority of the highest blood-lead level readings were: the scrap industry, accounting for 70 males, the lead battery sector with 33 males and a further 31 males were employed in other processes. In contrast to last year the number of males under surveillance with the highest recorded blood-lead levels has greatly reduced in the smelting, refining, alloying and casting sector (from 72 [7.2%] to 7 [0.5%]), the painting of buildings and vehicles sector (from 44 [10.3%] to 8 [2.3%]) and the glass making industry (from 30 [5.0%] to 3 [1.8%]). The number of males under surveillance with the highest blood-lead levels has increased in the scrap industry (from 18 [6.0%] to 70 [13.6%]).
The graph shows three cut-off points: the suspension levels under the 1980 Regulations (40µg/100ml); the suspension levels under the 1998/2002 Regulations (30µg/100ml); and the action levels under the 1998/2002 Regulations (25µg/100ml). No young females were under surveillance over the period.
The number of women with high blood-lead levels is small and so the proportion tends to fluctuate from year to year, making changes over time difficult to interpret.
In 1996/97 the proportion of female workers with blood-lead levels at or above 30µg/100ml was at a high of 7%. It then fell and fluctuated around the 4% mark from 2000/01 to 2004/05. In the last four years, this proportion has fallen further to around 1.2% in 2009/10.
Of the 7 females with blood-lead levels at or above 25µg/100ml in 2009/10, 6 were employed in the lead battery industry and 1 in other processes. This is similar to the number of females with the highest blood-lead levels under surveillance last year.
A worker whose maximum reading is at or above the suspension level will not necessarily be suspended from working with lead; a repeat measurement may be below the level, or in the case of females the worker may not be of reproductive capacity.
Figures 4 and 5 also show the proportion of workers suspended from work due to high levels of lead in their blood.
In 2009/10, 51 (0.7%) males were suspended from work due to excess blood lead levels. This was an increase from the 16 (0.2%) males suspended in the previous year of 2008/09. These 51 individuals were suspended a total of 64 times in the year 2009/10.
No females were suspended due to an excess of blood lead. The numbers of female workers involved are small and tend to fluctuate from year to year.
Neither the number of workers with measurements over the suspension level nor the number suspended should be interpreted as the number of lead poisonings, the purpose of the arrangements under the Control of Lead at Work (CLAW) regulations is to remove workers from exposure to lead before any toxic effects can occur.
