Lead: Destroying workers future

Not long ago we heard in the news that some toys made in China were sent back to the manufacturer due to their high lead content and thus the possibility of lead poisoning in children. Indeed, lead is a metal naturally found in the environment but it is very toxic and it has no known biological function in humans. Since it affects a developing nervous system, children are especially at risk, certainly in the age-group 6 months to 6 years. But lead can affect nearly every system of the body. Because it can cause so much damage, lead is in the US the only environmental toxin for which the children are routinely screened.

Exposure to Lead

Children may be exposed in many ways, either through the breathing in of lead dust or through the swallowing of objects that contain lead. Some examples of these are: toys, jewelry, lead-containing-gasoline exhausts, food made or stored in lead-glazed pottery and ceramics, food cans with lead soldering, candy wrappers, colored newspapers, plumbing pipes and paint chips in old houses, and even some food-additives and herbal medicines. Even though many countries have already banned the use of lead in all these products, countries with less stringent standards continue to bring these lead-containing products into the international market. Indeed, since lead is soft, easy to shape and relatively resistant to corrosion, it is often added to other materials to make them more durable or easier to work with. Children poisoned with lead will show lower IQ, impaired growth and development, impaired hearing, subtle changes in brain function, anemia, and at higher levels, kidney problems, seizures and coma. Up till now experts can not yet say that there is a blood-lead level at which there is no risk.

The danger to workers

But adults are at risk too, especially workers in following industries: manufacturing and recycling of lead batteries, paint and pigment manufacturing, spray-painting operations, welding and soldering, munitions plants and rifle ranges, glass-making and pottery industry, lead ore production and smelting, stained glass making, wire cable cutting and manufacturing, electronics, shipbuilding, painting (against corrosion) of bridges, towers or other steel structures, demolition of old houses, marine paint and fishing weights production, manufacturing of some plastics, magnetic imaging, solid waste incinerators, and energy generation.

Once absorbed, lead is found in all the tissues of the body, but eventually most of it accumulates in the soft tissues and bones. Although the body will slowly rid itself of lead once you are no longer exposed, this can take years, and some of the damages may be permanent. Unfortunately the early signs of chronic lead intoxication are not very specific. Workers may show signs of mild fatigue, emotional instability, difficulty to concentrate and memory problems, sleep disturbances, loss of appetite, irritability, high blood pressure, anemia, headache, muscular pain or pain in one or more joints, tremor, nausea, constipation or diarrhea, diffuse abdominal paint, menstrual disturbances, and diminished libido.

Because of the general nature of these symptoms, lead poisoning is often not suspected. Severe poisoning then leads to intermittent abdominal cramps, vomiting, kidney failure, blue-gray lead-line on the gums, infertility, miscarriages (lead crosses the placenta), inability to produce red blood cells, changes in the brain structure, nerve degeneration, convulsions and seizures, delirium, coma and death.

Several of the workers with lead poisoning that have asked the help of IOHSAD had actually these symptoms of severe intoxication. Most of them came from lead battery factories, and showed many signs of severe and long-time lead poisoning, like for example even the classical sign of ‘wrist-drop’ or ‘finger-drop’ whereby the hand or some fingers can not be straightened anymore due to nerve damage.

Once poisoned, the only thing that can be done in severe cases is ‘chelation therapy’. The patient is hospitalized and receives a chemical that binds to the lead in his or her blood and so helps it to be eliminated more quickly. But again, some damages already done will be permanent. The most important is thus PREVENTION and the employer of the plant is responsible for most of this.

Tackling lead poisoning

First of all, in many cases the manager could switch to lead-free substitutes, for example in solders, pigments and glazes. If this is not possible, secondary measures like adequate ventilation, exhaust of fumes and dusts, and even respirators should be provided.

Cleaning of the workplace has to use methods of wet cleaning and vacuum cleaning so that lead dust is not just been swept around. Clean areas for eating and drinking (and smoking) should be provided.

Healthy foods rich in iron, calcium and vitamin C, and low in fats will make that less lead is absorbed. The stomach must be kept full because lead is more readily absorbed when the stomach is empty. The workers must be given work clothes and shoes, and the facilities to shower after work and change to their own clothes. The work clothes should be cleaned at the work place and not brought home.

All this measures are needed in order to avoid bringing lead dust to the families of the employees. Regular environmental monitoring of the lead in the work place is also necessary and the results must be announced to the workers. The permissible exposure limit is set at 50 µg/m3 averaged over an 8 hours period by OSHA.

Responsibility of the employer

Very important also is medical surveillance of the employees. The physical examination should focus on the gastrointestinal, hematologic, renal, reproductive and neurologic systems. The lungs should also be evaluated in workers wearing respirators. Workers with neurologic symptoms may need nerve conductions studies and neuropsychiatric evaluation.

Laboratory tests must focus on blood lead level, on zinc protoporphyrin (ZPP), hemoglobin, hematocrit, creatinine and BUN, liver enzymes, CBC, and urinalysis. Blood lead level and ZPP are to be taken every 6 months if these values were normal at last test (otherwise more regularly). A normal ZPP is less than 100 mg/dl and different agencies set different standards for the blood lead level.

Most of the time the OSHA standard of 40 µg/dl is used, but since recent research has found out that levels below this standard have already subtle, subclinical neurologic effects, there is a tendency in Western countries to set the blood lead level lower than this. For example, for the Washington State the level of concern is 25 µg/dl, and for the US government it is 10 µg/dl. As reference it might be good to know that people not exposed to lead have less than 10 µg/dl lead in their blood.

It is our experience in IOHSAD that companies do not include the ZPP test, and that the blood lead level is often taken by not very reliable laboratories. Workers who have first their blood tested in the company-assigned laboratory and immediately thereafter in the UP Manila Occupational Health Department always had higher values in UP than in the company laboratory…. And we should not forget that also the children of the workers who bring home lead on their clothes and shoes should be able to undergo some testing.

It is a pity that –due to ‘shortage of occupational health and safety inspectors’- more and more responsibility for OHS is left to the companies themselves. This could be feasible in countries with strong labor union movements where management‘s and workers’ goals and needs can be balanced, but in a country as the Philippines, where unions have very little say, and where decisions are usually made solely by management (whose primary goal is of course profit-making), the health of workers and their families is usually left to the mercy and goodwill of the employers. This is the price paid by the majority of the Filipino people because the US-inspired liberal free market economy and world-view.