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news - dry cleaning: clean but deadly

WDDTY vol 18 no 6

Perchloroethylene – also known as perc, PCE, perchlor, perclene or tetrachloroethylene – has been the most widely used chemical in the dry-cleaning industry for the past 50 years. It's a volatile organic compound (VOC) now used by 85 per cent of dry cleaners. Yet, there are persistent concerns as to its safety, particularly for those who are regularly exposed to it. Research shows that it can cause a laundry list of adverse health effects – from headaches and dizziness to cancer and liver damage.

Dry cleaning is though to have originated in France, in 1845, when dye-works owner Jean-Baptiste Jolly accidentally spilled lamp oil (kerosene, a petroleum-based solvent) on a soiled tablecloth. When the tablecloth dried, the stain was gone. Jolly is credited with coining the term 'dry cleaning' to differentiate it from 'wet cleaning' – soap and water washing. He then went on to create a fir, Jolly-Belin, that was Europe's first professional dry-cleaning service, cleaning other people's clothes using solvents instead of water.

Since then, a wide range of solvents have been used for the process of dry cleaning – from the highly flammable kerosene to the ozone-eroding greenhouse gas CFC (chlorofluorocarbon) – 113. However, for the past 50 years, the most popular dry-cleaning agent worldwide has been perchloroethylene, or perc. It's considered ideal because it's non-flammable, gentle to most fabrics and an excellent cleaner.

But while the chemical may work wonders on your clothes, perc may be extremely hazardous to your health. There's growing evidence that exposure to perc can cause neurological, liver and kidney damage as well as increase the risk of cancer. It also contaminates the air, food and water. Many countries have now imposed stringent regulations for the control of perc exposures and emissions. But are they enough?

neurological effects

In the latest report on perc-relatedhealth effects, a team of scientists at New York City's Columbia University made a shocking discovery: that exposure to perc can increase the risk of schizophrenia by 200-300 per cent (Schizophr Res, 2007; 90: 251-4).

The study examined the relationship between parental occupation as a dry cleaner and the risk for schizophrenia in their children. The researchers looked at a total of nearly 89,000 children born in Jerusalem from 1964 through 1976, and followed them from birth to 21-33 years of age.

Out of 144 dry cleaning families, there were four cases of schizophrenia – a much higher incidence than expected within the general population. The researchers attributed this increased risk to perc exposure, concluding that the chemical "warrants further investigation as a risk factor for schizophrenia".

Although further studies need to be carried out of verify this particular link, it has been known for some time that perc can have adverse effects on the brain. Since the 1970s, clinical studies have shown that exposure to perc can cause neurobehavioural problems- those related to emotion, behaviour and learning. This may be due to the depressive effect of perc on the activity of the central nervous system, which relays messages to and from the brain to all other parts of the body. The resultant symptoms can range from mild to serious, depending on the level of exposure.

It's also been shown that long-term exposure to airborne perc – as shown by studies involving dry-cleaning workers and people living near dry-cleaning facilities in Germany, for example – can have a negative impact on neurobehavioural functions such as visual colour discrimination and rapid visual-information processing (Environ Res, 1995; 69: 83-9). In this case, the chemical/air concentrations were relatively low (1.36 mg/m3), yet even this amount of exposure affected those exposed for several years.

In another German study of acute perc exposure, visual and contras-perception problems were surprisingly observed even at low inhalation levels of 50 ppm (parts per million) (Int Arch Occup Environ Health, 1990; 62: 493-9).

Similarly, a more recent study in New York City compared six residential families and the workers at a day-care centre in two apartment buildings that had dry-cleaning facilities on the ground floors. Compared with matched controls, those exposed to airborne perc, despite being healthy, performed poorly on tests of colour vision, perceptual speed, and sensory-motor and cognitive functions. They were also more likely to suffer from central nervous system symptoms (Environ Health Perspect, 2002; 110: 655-64).

Short term exposure (less than 14 days) can cause dizziness, headache, light-headedness, poor balance, visual impairment, reduced test scores and reaction time, and attention deficit and eye-hand coordination problems (Townsend Lett Docs, 2007; June: 29-31).

other toxic side-effects

As well as targeting the central nervous system, perc can also cause damage to the kidneys and liver – whether at extremely high doses over the short term or at low levels over the long term (Am J Ind Med, 1991; 20: 601-14); Townsend Lett Docs, 2007; June: 29-31; WHO Regional Office for Europe. Ch 5.13 Tetrachloroethylene, in Air Quality Guidelines, 2nd edn. Copenhagen, 2000). In one Italian study, changes in various markers suggestive of diffuse kidney abnormalities were evident in dry-cleaning workers exposed to very low levels (15 ppm) of perc (Lancet, 1992; 340: 189-93).

Even more worrying, occupational exposure to perc has been linked to reproductive problems, including spontaneous abortion, menstrual and sperm disorders, and reduced fertility (Townsend Lett Docs, 2007; June: 29-31). There's also evidence of birth defects when women are exposed to perc during pregnancy (Toxicol Ind Health, 2002; 18: 91-106; Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Tetrachloroethylene (Update). US Public Health Service, US Department of Health and Human Services, Atlanta, GA, 1997).

Yet another concern is that perc exposure may increase the risk of cancer. According to a US Environmental Protection Agency (EPA) fact sheet, studies of dry-cleaning workers exposed to perc and other solvents suggest an increased risk for cancers of the oesophagus, kidney, bladder, lung, pancreas and cervix (www.epa.gov/tin/atw/hlthef/tet-ethy.html). These data, along with evidence from animal studies, led the International Agency for Research on Cancer (IARC) to classify perc as a Group 2A substance, one that is "probably carcinogenic to humans".

While those who are occupationally exposed to perc are especially vulnerable to its carcinogenic effects, the general public is also at risk. A 1996 analysis by Consumer Reports found that one out of 6700 people wearing freshly dry-cleaned clothes once a week could be expected to develop cancer as a result of inhaling the perc fumes clinging to the fabric (Townsend Lett Docs, 2007; June: 29-31).

safer alternatives

As evidence accumulates as regards perc's health and environmental risks, many countries are placing more and more restrictions (and fines) on dry-cleaning businesses. In the US, the state of California has announced a statewide ban on toxic dry-cleaning chemicals and equipment, to be in place by 2023. As a result, a number of cleaning firms are already offering safer alternatives to perc.

Once increasingly popular option in the US and UK is silicone-based siloxane D5, better know as 'Green-Earth'. This solvent degrades to sand, water and carbon dioxide, and poses no health risks to workers, at least according to the GreenEarth website (www.greenearchcleaning.com). However, siloxane solvents are made using chlorine, which may release dioxins – cancer causing environmental pollutants – into the air. Siloxane is also highly flammable and "may be a cancer hazard", according to the EPA (Townsend Lett Docs, 2007; July: 54-60).

Another option is liquid carbon dioxide (CO2), which has no reported health effects and came top in a review of alternative cleaning methods by Consumer Reports. Also, it produced better results than conventional perc cleaning. And cleaning with CO2 doesn't add to global warming because it's captured from industrial and agricultural emissions. However, the detergents used in the process contain volatile organic compounds (VOCs), some of which are toxic and/or carcinogenic, and contribute to ground level ozone.

By far, the safest cleaning alternative is wet cleaning, which uses water in specialised machines along with specially formulated detergents and additives. The process is one of the two methods considered environmentally preferable by the EPA (the other is CO2). Nevertheless, wet cleaning may not be suitable for all garments, and how your clothes turn out depends on the skill of the workers. But, at least, you aren't putting your health at risk.

Written by Joanna Evans

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