McPherson Square protesters have hunkered down for the cold weather. (Bill O'Leary/WASHINGTON POST)

Mayor Vincent C. Gray called on the National Park Service today to remove protesters from McPherson Square to “allow for elimination of the rat infestation, clean up, and restoration” of the downtown park.

In a letter to Park Service Director Jonathan B. Jarvis, Gray suggests moving the McPherson protesters, who have camped in the park since October, to a separate encampment at Freedom Plaza.

Because both sites are on Park Service land, Gray does not have the authority to directly order an eviction. But today’s demand is Gray’s most dramatic pronoucement yet on the ongoing protests.

His letter was accompanied by a memorandum from the city’s health director reporting that both encampments are at risk for outbreaks of “communicable disease, hypothermia or food borne illness.”

Mohammed N. Akhter reported that the city “must now reassess and take steps to protect the health and safety of the demonstrators, as well as District residents and visitors.” The memo followed several dozen visits to the encampments.

The McPherson Square site, Akhter said, “has some serious concerns that should be addressed immediately.” The problems include an ongoing risk of hypothermia, fire threats from the use of candles and propane heaters, inadequate food sanitation and a rodent infestation that is “clearly visible even during daylight hours.”

View Photo Gallery: Inside Occupy D.C.

”Several rodent burrows were noted by staff and rodents were seen inside of camping tents, as well as within the makeshift kitchen tent,” Akhter wrote.

At Freedom Plaza, he noted, there is a “greater attempt being made to adhere to good sanitary practices with waste disposal and food preparation.”

Sam Jewler, a media organizer for the McPherson protesters, said the concerns cited by Akhter are overstated and otherwise managable. “We haven’t had any hypothermia. We haven’t had any disease problem,” he said. “We’ve complied with everything they’ve asked us to do. There’s no reason that wouldn’t continue to be the case.”

As for the rodents, Jewler said, “We do have rats; most public parks have rats. We hate rats as much as anybody else does. We’d love to work with them on getting the rats out. We don’t think that requires getting the tents out.”

In an interview Wednesday with The Washington Post, Akhter said conditions at McPherson Square were “no different than refu­gee camps” — a characterization Jewler called “totally inappropriate.”

Rep. Darrell Issa (R-Calif.), the chairman of the House Oversight Committee, issued a statement late Thursday calling the city’s report “disturbing” and “a blunt assessment of the situation created by the National Park Service’s decision to ignore laws designed to protect the public.”

Issa, who has asked the Park Service to produce documents explaining its policy toward the protests, said it “has so far been more interested in making excuses than protecting the public.”

Bill Line, a Park Service spokesman, said Gray’s letter has been received, but he had not read the letter and did not have comment Thursday evening. Line reiterated earlier comments that the Park Service must adhere to court rulings protecting protesters’ right to maintain a “24-hour vigil” on federal land.

Akhter did not recommend any particular course of action in the memo but told Gray that city agencies are “working together to develop a monitoring and public education plan to reduce the risk of these concerns from developing into a major health crisis.”

Combining both protests at Freedom Plaza would “present some challenges,” including increased costs and security needs, said Kevin Zeese, an organizer at that encampment. Moreover, he said, “The two camps have different personalities and we do not want to lose the personality of Freedom Plaza.” Zeese said he and his fellow protesters are “currently looking at how best to proceed if the mayor’s vision becomes a reality.”

In his letter to Jarvis, Gray reiterated his requests for reimbursement for the costs incurred by the protests and said the Freedom Plaza camp must be subject to “regular safety and compliance checks.” A mayoral spokesman, Pedro Ribeiro, declined to elaborate on the letter Thursday night.

Gray’s attitude toward the protests has been complex and evolving. He has generally supported the activists’ right to protest, but he told the Post last month that he was confused by the Occupy movement’s goals. “What is frustrating for me, and I think of my own causes, is, what is the desired outcome here?” Gray said. “Where are you trying to get to? . . . You see signs that read, ‘End corporate rule.’ Well, how do you do that?”

More recently, Gray has publicly welcomed the efforts of several Occupy-affiliated protesters who launched a hunger strike in support of District autonomy.

City police have generally taken a hands-off stance toward protesters, mainly arresting those who have deliberately blocked traffic after ignoring official warnings. But Gray has had to deal with calls from D.C. business leaders who want the protests to end — such as Board of Trade CEO Jim Dinegar, who said in a December radio interview that the city was being “abused by the Occupiers” and that McPherson Square would be “a toxic waste dump” after protesters leave.

Jewler noted that an influx of protesters is expected next week for an ”Occupy Congress” march set for Tuesday. “If they think they’re going to kick us out at that point, it’s not going to be easy,” he said. “It’s not going to be pretty.”

The letter:

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