Hawaii’s first-in-the-nation ban on chlorpyrifos could set a precedent for other states looking to ban the toxic insecticide that can trigger headaches, nausea, and paralysis, environmentalists told Bloomberg Environment.

Hawaii Gov. David Ige (D) signed the bill (S.B. 3095) June 13, making the state the first in the U.S. to ban the common ingredient in certain pesticides made by companies including Syngenta, Dow AgroSciences, and BASF Plant Science. Ige’s office pointed to chlorpyrifos’s...