AUGUSTA — Maine lawmakers gave close scrutiny Monday to a bill that could wipe out dozens of local ordinances that are aimed at protecting the environment and public health from the unintended effects of pesticides.

The legislation, offered by the administration of Republican Gov. Paul LePage, would disallow cities and towns from placing restrictions that are more stringent than those in state law on a whole host of chemicals that are used to do everything from making lawns greener to killing invasive species of insects.

Commissioner of Conservation, Forestry and Agriculture Walt Whitcomb said a confusing “patchwork” of controls were being enacted at the local level. He noted that 27 Maine communities had enacted local ordinances to control the application of pesticides. Whitcomb said many of the local measures were stricter than state and federal laws and were often being applied to products that have been deemed safe for controlled use by the U.S. Environmental Protection Agency.

Representatives of numerous businesses that depend on pesticides or apply them professionally testified for the bill. They said the state already has a vigorous licensing process, and town-by-town bans could have the unintended consequence of limiting the effectiveness of pesticides applied to protect public health or crops important to the state’s economy. They also said towns that resorted to outright bans would likely have private homeowners buying and applying chemicals in unsafe ways, compared to a licensed professional.

The bill was heard by the Legislature’s State and Local Government Committee. Whitcomb said the state’s Board of Pesticides Control should be the final arbiter of the application of pesticides.

“Local towns or cities do not have staff to analyze the way that our Pesticides Control Board and our scientists that are on that board (analyze) the products and their use,” Whitcomb said. He offered other examples in state law, including the regulation of fish and wildlife and the registration of motor vehicles, where the state does not cede control to local municipalities.

Lawn care company representatives and golf course superintendents also spoke in favor of the bill, saying town-to-town ordinance changes could create unfair advantages or jeopardize businesses and jobs.

“State pre-emption would also ensure the state maintains its authority to guide how pesticides are used on properties that they own and manage and reduce the negative implications on public health caused by numerous contradictory, confusing and overlapping local ordinances,” Scott Descoteaux, a service manager for the lawn care company Trugreen, told the committee.

Chuck Cotton, a Biddeford resident representing Lucas Tree Experts, said that of the company’s 280 Maine workers, about 120 hold state pesticide applicator licenses. Cotton said the increasing number of local ordinances was making it harder to do business.

“The state has a well-defined set of regulations and standards outlining for us how we need to conduct our pesticide application business,” Cotton said.

But opponents of the measure, including several environmental advocacy groups and representatives from towns with more stringent pesticide laws, said a one-size-fits-all approach does not work for Maine’s many diverse communities. Opponents also said the measure undermines local control and was a dangerous attempt to roll back restrictions that are working well.

Mary Ann Nahf, who chairs the town of Harpswell’s Conservation Commission, spoke in opposition to the change, saying her town adopted ordinances that are more stringent than the state’s in order to protect more than 200 miles of shoreline and the more than 50 percent of the town’s residents who derive their livelihoods from the ocean, either directly or indirectly.

Harpswell’s ordinance bans the use of a pesticide that kills moths but can also harm lobster if the chemical gets into the ocean. Nahf said lobstermen prompted the town’s ordinance when they discovered an increase in dead lobsters after the town had sprayed a pesticide to control a browntail moth outbreak in 2002 and 2003.

She said the town ordinance banning the use of the pesticide, known as an insect growth regulator, came in 2004. Nahf said the town’s ordinance eventually led the state to tighten its own regulations around the use of the chemical near the ocean, but only after four years had passed.

“We realize that pesticides and their use is complex,” Nahf said. “The Board of Pesticides Control is available to answer questions and we applaud its efforts to have the regulations and town ordinances readily available online. However, in the case of browntail moth controls, the time necessary for changes to be enacted statewide could have been detrimental to Harpswell’s marine economy.”

Harpswell also has a waiver process that allows for the use of pesticides on agricultural lands, and none of the 27 local ordinances impose an outright ban on pesticide use, according to Garrett Corbin, a lobbyist for the Maine Municipal Association, who spoke in opposition to the proposed bill. Corbin also noted that those who have suggested a “snowballing” effect of new local ordinances regulating pesticides were exaggerating.

He said three towns have recently passed new ordinances, but in the last 30 years only 27 local ordinances have gone on the books and many of those regulate only the use of pesticides by municipal government. “If that is a snowballing growth of ordinances, it is the slowest-growing snowball I’ve ever heard of,” Corbin said.

He said MMA wasn’t taking a stance against the use of pesticides and the organization has also testified against bills that would enact statewide bans on pesticides as well.

Even if the bill were passed into law, Sen. Tom Saviello, R-Wilton, the Senate chairman of the Legislature’s Environment and Natural Resources Committee, suggested it may not withstand a challenge in the courts. Saviello served for 16 years on the Board of Pesticides Control, including eight years as its chairman.

He said the Maine Constitution protects home rule and local control for cities and towns, and he distributed a copy of a Maine Supreme Judicial Court ruling in a 1990 case between Central Maine Power and the town of Lebanon, which passed an ordinance prohibiting the aerial application of pesticides. Saviello said the bill was before the Local and State Government Committee because it was about limiting a municipality’s ability to govern itself.

“That’s what this is about,” Saviello said. “We have allowed our municipalities to develop their own ordinances as long as they are at least equal to if not more restrictive than the state law.”

The bill will be scheduled for a committee work session before it faces additional votes by the full Legislature.