The life of the American trucker has been romanticized in stories, songs, and film since the first eighteen wheels hit the asphalt, despite the grueling and lonely realities of the job. Now, however, a study reported by WebMD shows that those who are routinely exposed to diesel fumes may be at a higher risk for amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease.

Aisha Dickerson, a postdoctoral research fellow and the author of the study, claims that truck drivers and others with long-term diesel exposure had a 40 percent higher risk of developing the disease, compared with those who had no such exposure. It isn’t only truckers who are at risk — diesel fumes are also an occupational hazard for tool cutters, construction workers, dock hands, or anyone who works in an industrial setting. According to Dickerson, the risk is strongest for those who hold these positions for a period of 10 years or longer. She goes on to add that in some cases, symptoms won’t manifest themselves until years after exposure to the diesel exhaust has ended, but that it’s too late to reverse the damage at that point.

Dickerson and her colleagues were spurred into investigating this matter when a series of prior studies seemed to suggest a correlation between diesel exposure and ALS. The earlier findings were not as dire, however, showing only a 20 percent higher instance of ALS in truck drivers and construction workers — and, interestingly, only in men, suggesting that the diesel fumes themselves might not be the root cause of the issue. While it’s true that diesel fuel contains a myriad of toxic compounds — including carbon dioxide, carbon monoxide, ,and formaldehyde — there is still a chance that these compounds only hasten the arrival of a disease that would eventually have occurred in the individual anyway. Further research is therefore needed to determine whether there might be another, more definitive explanation for the link.

ALS is a progressive neurodegenerative condition that attacks the nerve cells responsible for muscle movement, causing the decline of motor function and respiratory activity. There is no cure, and symptoms are crippling and eventually fatal. Renowned physicist Stephen Hawking, who fought a well-publicized and nearly lifelong battle with ALS, recently passed away at the age of 76.