WEDNESDAY, Aug. 5, 2026 (HealthDay News) — Exposure to pesticides on the job can increase a person’s risk of amyotrophic lateral sclerosis, or ALS, a new evidence review says.

Workplace exposure to herbicides and insecticides is linked to a 60% to 70% increased risk of ALS, researchers reported Aug. 4 in the journal Occupational & Environmental Medicine.

And overall, men who’ve been exposed to these chemicals could be twice as likely to develop ALS compared to those who haven’t, researchers said.

“The findings of this review add to the evidence that occupational exposure to pesticides may increase the risk of ALS and should encourage the implementation of interventions aimed at reducing exposure during occupational pesticide use,” concluded the research team led by Sabrina Gravel. She is an associate professor of public health with the University of Montreal.

ALS, also known as Lou Gehrig’s disease, is a degenerative disorder that progressively damages the motor neurons in a person’s brain and spinal cord.

ALS patients suffer from muscle weakness, twitching, stiffness and cramping, but eventually have trouble speaking, swallowing and breathing. The average survival time after diagnosis is about three years, according to the ALS Association.

Pesticides are known to be toxic to brain cells, but there’s not much research regarding their potential long-term effects on the brain and nervous system, researchers said.

For the new review, researchers pooled data from eight previous studies involving more than 1,700 people with ALS, and three studies that looked at more than 450 people with unspecified motor neuron diseases.

Results showed that any workplace exposure to pesticides increased ALS risk by 60%, researchers said.

And based on results from three studies, any exposure to high levels of pesticides nearly tripled risk of ALS compared to no exposure. Any exposure to lower levels of pesticides appeared to double risk.

Looking at specific types of chemicals, herbicides were associated with a 70% increased risk of ALS, and insecticides or fungicides with a 60% increased risk.

However, researchers said more investigation is needed to fully explore the risks posed by farm chemicals.

The researchers called for stronger studies that detail exposure levels and account for other factors that could be driving the higher rates of ALS.

More information

The ALS Association has more on ALS.

SOURCE: BMJ, news release, Aug. 4, 2026