A Suffolk County scientist and several East End town leaders are among those raising concerns about chemicals used across Long Island to combat mosquito populations.

Kevin McCallister, a scientist and marine biologist, says the chemical methoprene should be banned from use in the county's salt water marshes.

It is already banned in coastal areas in Connecticut, and Southampton Town Supervisor Jay Schneiderman is one of the East End supervisors calling for Suffolk to stop spraying the chemical.

"We spend so much time and money trying to improve water quality, and then we introduce toxins from helicopters," he says. "It doesn't make sense."

Suffolk officials say they spray methoprene to combat West Nile virus. They also say that the county has used the chemical for more than 20 years.

"Extensive studies consistently show that methoprene does not negatively impact lobsters or the environment," a statement from County Executive Steve Bellone's office said.

But environmentalists say the compound is not effective in a salt water marsh to begin with.

McCallister says it's freshwater mosquitoes that carry the virus.

"It does not exist in salt marsh mosquitoes," he says.