People who regularly work with "safe" solvents such as paint or degreasers face an increased risk of thought and memory problems as they age, according to a recent study.

The study, published in the journal Neurology on May 13, details how researchers determined that individuals who work in construction or utilities face heightened risk of advanced cognitive decline as they age. They associated this decline with regular exposure to regulated solvents such as benzene, chlorine, and petroleum.

According to the study, researchers interviewed and assessed the cognitive capabilities of 2,143 retirees from the French national utility company Electricite de France/Gaz de France.

Through questionnaires and interviews, the researchers measured each participant's past exposure to benzene, found in dyes, detergent, rubber and plastic; chlorinated solvents, found in dry cleaning products, paint removers, degreasers, and engine cleaners; and petroleum solvents, used in varnish, paint thinner, paint, and carpet glue.

The retirees were followed from retirement until they reached the age of about 66, when they were asked to take a series of tests in a follow-up assessment of their cognitive abilities. They found that in an average of 10 years after retirement, 59 percent of the participants faced minor to moderate cognitive impairment and 23 percent of the participants showed heavy impairment - scoring poorly on four or more tests out of eight total.

Predictably, the researchers were able to determine that the workers who had more frequent and recent exposure to harmful solvents prior to retiring were significantly more likely to develop cognitive impairment. Chlorinated solvents proved the worst in this regard, making those frequently exposed to it 65 percent more likely to have impaired memory, visual attention, and fluid thinking, compared to workers not exposed to the solvents.

It should be noted that while the aforementioned chemicals are highly controlled products in most countries, only immediate ramifications are often considered when discussing workplace safety precautions. The authors of the study write that it is their hope that statistics like these can change that.

Protecting worker health, they write, will not only protect their brains as they age, but will also reduce health-care costs and allow workers to work past the current average retirement age.