The state Department of Conservation and Recreation is coming under fire yet again for leasing state land to private entities at below-market rates, but this time even one of the critics is being accused of having his own sweetheart deal with the state.

The agency has taken flak in the past for lax oversight of its lease agreements. In some cases, the agency failed to collect payments from renters, ignored lease expiration dates, or renewed agreements in perpetuity at ridiculously low rates.

Once state officials acknowledged the problem, they called for a state audit and vowed to negotiate leases that maximize value for taxpayers. The best example is a parking lot on state-owned land along Storrow Drive in Boston across from the Massachusetts Eye and Ear Infirmary. For more than 20 years, the infirmary had been paying $120,000 a year to lease the parking lot; after the contract was put out to bid in 2012, the state brought in a new vendor who is paying about $1 million a year.

Now two prominent environmentalists are raising concerns about a DCR plan to lease seven-acre Daly Field along the Charles River to a group that includes Simmons College. In 2012, the Legislature passed and the governor signed into law a bill that allowed, but did not require, DCR to enter into the lease. Daly Field sits between a state ice rink and Community Boating, which also lease land from the state.

Simmons has agreed to spend $5 million installing a turf football field, six tennis courts, a turf field hockey field, and a turf baseball diamond on the site. In return, Simmons, Brighton High School, and the Allston Brighton Little League would receive preferred usage times.

In a letter to state officials, George Bachrach, president of the Environmental League of Massachusetts, and Robert Zimmerman, executive director of the Charles River Watershed Association, called the proposed Daly Field lease arrangement a “bad deal” for taxpayers. They say the legislation authorizing such a lease was flawed because it exempted the project from public bidding.

The two environmentalists also said Simmons is essentially gaining the use of state land for 20 years (with an option to renew for another decade) without having to pay any rent. “Simmons is essentially getting the land for free,” Bachrach and Zimmerman said. “While it has maintenance and utility responsibilities, the college would assume these costs regardless of where it built its athletic facilities.”

Bachrach and Zimmerman also said the Daly Field deal fails to provide enough public access. They say the lease should spell out that the facility will be open to the general public any time Simmons, Brighton High School, and the Allston Brighton Little League are not using it.

Simmons officials said the proposed public-private partnership with the state is a good deal for taxpayers since it will bring state-of-the-art athletic facilities to a field that has been in disrepair for more than 20 years. They said the fields will be open for use from 6 a.m. to 11 p.m. spring, summer, and fall and during daylight hours in the winter. Simmons, Brighton High School, and the Allston Brighton Little League said they will use the facilities roughly a quarter of the time, with public access, subject to DCR permits, the rest of the time.

Simmons officials also noted they will be making two payments of $250,000 to the state as part of the deal.

What makes this debate about a public land lease so unusual is that Zimmerman’s own organization leases a building from the state on attractive terms. His organization just signed a three-year, no-bid lease extension with DCR to occupy a 3,600-square-foot office building from DCR at $100 a month even after it failed to fully live up to the terms of its last lease.

The so-called Ouimet building is ideally located at the Leo J. Martin Golf Course on Park Road in Weston, which is near the intersection of Route 128 and the Massachusetts Turnpike, as well as the Charles River.

Zimmerman said his organization’s deal with DCR is not the same as the proposed Daly Field deal. “Daly Field is . . . [a] disposition of public trust land via a 30-year lease. Our license is not,” he said, noting that the watershed association’s lease extends for just three years. He also said his organization’s original lease, granted in 2006, was publicly bid. The lease expired in 2010 and was not renewed, but the watershed association continued to occupy the building and pay $100 a month in rent.

Zimmerman also noted that the watershed association is responsible for all maintenance and repairs of its offices (an estimated $150,000 spent over the last eight years) and installation of a new $30,000 septic system.

“CRWA is a small environmental nonprofit with a mission to protect and restore the Charles River,” he said. “We spend over $1 million a year on our mission, which is closely aligned with DCR’s stewardship responsibilities for the Charles.”

Bachrach, in an email, echoed Zimmerman’s comments. “CRWA’s mission largely supports DCR’s mission, while Simmons’ does not,” he said. “Most importantly, according to the appraisal done for the Commonwealth, Simmons is paying nothing for seven valuable acres of land along the Charles River, inside the city of Boston!! There may be a story here, but if you think it is about CRWA and not the Simmons/Daly Field deal, then someone is missing the forest for the trees.”

Dan Cuddy, a community activist and a member of the Friends of Daly Field group, thinks Zimmerman is “inconsistent” in his reasoning. “His organization gets to use a valuable piece of state property, without it being put out to bid, at a rate that is way below its fair-market value,” Cuddy said. “Yet at the same time, he has the audacity to ask us to do what he doesn’t do himself. That’s unfair.”

A DCR spokesman maintains that the agency was not required to put the Ouimet building out to bid, but former inspector general Gregory Sullivan disagrees.

“Look, the mission of the Charles River Watershed Association is truly admirable,” said Sullivan, who is currently the research director at the Pioneer Institute. “But the procurement laws require DCR to have put the Ouimet property out to bid in order to get fair-market value for taxpayers. What DCR is doing is illegal and it’s wrong no matter how well intended it is. The idea that they would renew the Ouimet agreement at pennies on the dollar of its value to me is ludicrous and outrageous.”

Jack Murray, the commissioner of DCR, said he didn’t up the association’s rent because the lease requires the organization to install the new septic system. Yet the septic system was also required by the old lease but wasn’t installed. “Well, the benefit is that there will be a new septic system that hadn’t been delivered before,” Murray said.