State Sen. Mike McGuire has introduced a sweeping bill that would legalize and regulate the medical marijuana industry from cultivation to consumption and all the steps in between.

The bill, SB 643, passed out of the state Senate’s Business and Professions Committee on April 20 and will receive a hearing in the Senate’s Governance and Finance Committee on Wednesday.

The Compassionate Use Act of 1996 and subsequent state legislation exempted qualified medical patients and their caregivers from state criminal sanctions related to possession, cultivation and transportation of limited amounts of marijuana. Nevertheless, a lack of statewide regulation has resulted in uncertainty about the legality of some medical marijuana cultivation and distribution activities.

“California needs a statewide comprehensive regulatory program for medical marijuana,” McGuire said. “Since the voters of California passed Proposition 215 medical marijuana cultivation and consumption has exploded across the Golden State and the country. This legislation would put into place what should have been implemented two decades ago.”

In addition to Marin County, McGuire’s legislative district also includes Mendocino, Humboldt and Trinity counties, which account for an estimated 70 percent of the marijuana grown in the western United States.

McGuire, D-Healdsburg, said illegal growers — often trespassing on national park land — have cut down thousands of acres of trees and dumped pesticides, insecticides, rodenticides, fertilizers and huge amounts of sediment into waterways.

“In fact, marijuana grows are the No. 1 source of sediment and nutrient loads in Northern California rivers and streams,” McGuire said.

McGuire said rogue growers are also diverting water from drought-stricken rivers and streams.

A state Department of Fish and Wildlife study released last month estimated the number of marijuana plants being grown in four watersheds in Humboldt and Mendocino counties and determined that during drought conditions the water being used to grow the plants exceeds the stream flow in three of the four watersheds.

“They are literally sucking our rivers and streams dry,” McGuire said.

McGuire’s bill would create a Bureau of Medical Marijuana Regulation within the state’s existing Department of Consumer Affairs. The legislation would give the bureau until Jan. 1, 2018, to develop procedures for the issuance of conditional licenses for cultivation, manufacture, transportation, storage, distribution and sale of medical marijuana within the state.

The bureau, in consultation with the state Water Resources Control Board, also would be charged with adopting regulations to ensure that licensed medical marijuana growers don’t threaten the state’s environment.

After a quick review of the lengthy bill on Monday, George Bianchini, founder and CEO of Medi-Cone, a Marin-based collective that grows and sells medical marijuana, said he had some concerns about the bill.

Bianchini said the legislation reminded him of SB 1262, which failed to gain support in 2014 when state Sen. Lou Correa introduced it.

“I believe these are bills being written with big money behind them pushing for the corporate control of cannabis in California,” Bianchini said. “It doesn’t take into consideration existing operators.”

Bianchini said he was concerned about the lack of detail in the bill specifying how the permits would be allocated, and the cost associated with new regulations proposed for the transportation of medical marijuana.

McGuire, however, said the issuance of permits would remain under the control of local jurisdictions.

“This is why our district needs to take the lead on this issue,” McGuire said. “We have more family farmers growing cannabis than anywhere else in the nation.”

Scot Candell, a San Rafael lawyer who has represented various medical marijuana collectives, said his concern is that the bill regulates to a degree that it might spur more black market activity.

“It may border on over-regulation, but I think its goals are noble,” Candell said. “It requires lab testing, which I think should be required.”

Four similar bills are pending in the Assembly. Candell said before recreational use of marijuana was legalized in Colorado that state created a regulatory framework for medical marijuana that made the transition smoother. He believes that is what legislators in Sacramento are trying to do.

Candell said, “Our industry in California is chaos, and they’re trying to organize it prior to the 2016 vote.”