For almost a decade, Simón López, the special education coordinator at Boston’s Sarah Greenwood School, has been fighting against the school district that employs him. He has lobbied principals, written letters to the revolving door of superintendents in the district, made his case to school board members and even contacted state education agency officials.

All to no avail.

His cause? López maintains that the Sarah Greenwood School’s coveted dual language program, which teaches students in both English and Spanish, is violating civil rights laws by intentionally excluding many students with emotional disabilities — including some native Spanish speakers who would benefit from a bilingual approach.

Many of the excluded students “have proven that they have the ability to learn a second language if given the opportunity,’’ López said.

The district runs five other dual language programs in addition to the one at Sarah Greenwood in Dorchester — four more in Spanish and a fifth in Haitian Creole. All of them refuse admittance to certain categories of special education students, including those with developmental delays and emotional impairments, according to the district.

In three city schools, including Sarah Greenwood, the students with these disabilities attend a shadow school of sorts, spending their days learning mostly, or entirely, separate from the rest of their peers. The district confirmed that they are denied any access to the bilingual instruction happening in the same building.

This, according to experts, is a violation of state and federal laws that prohibit districts from excluding kids from any educational programs just because they have a disability. It also violates laws that require students be taught in the most inclusive environments possible, given their disabilities.

“You can’t just stick these kids in the corner,’’ said Elena Silva, director of PreK-12 for the Education Policy Program at New America, a Washington, D.C., based think tank that has studied both special and bilingual education.

Boston schools Superintendent Brenda Cassellius would not say when, or if, all students with disabilities will become eligible for the city’s dual language programs. But she said the district plans to expand its bilingual offerings, including for students with disabilities, and reduce the number of special education students who are isolated from their peers.

At Sarah Greenwood, 58 students with disabilities learn in isolated classrooms and are ineligible for the dual language program, according to district data. Even if the district determines they no longer need special education services, the students have to find a new school. After being excluded from the dual language program until that point, most aren’t prepared to transfer in.

López said that over the years he has worked with several families whose children would have been a good fit for the bilingual program but were barred. One family, who declined to be interviewed for this piece, moved to Boston from Puerto Rico in 2017 after Hurricane Maria ravaged the island, López said.

The family’s first-grader qualified for special education services for an emotional impairment, and the district placed him at the Greenwood School’s specialized program for such disabilities. His parents were overjoyed — initially —because they thought he would also be able to participate in the school’s dual language program, easing his language and cultural transition.

“They started crying when I had them in my office and told them, ‘No, he will not be able to participate in the dual language program,’’’ López recalled.

In general, any Boston family can list a school with a dual language program as their top choice in the district’s assignment process, but students with disabilities who qualify for more specialized services have more limited options.

It’s an oversight in a network of dual language programs that, by all accounts, was designed with the needs of immigrant communities in mind.

Across the state and country, some dual language schools have increasingly come under criticism for the opposite: enrolling primarily or even exclusively native English speakers, often from wealthy, highly educated families who consider bilingualism an asset for work and travel. These families advocate for the programs in their children’s schools or move into formerly immigrant neighborhoods and take up the seats in long-running bilingual education programs. At the same time that immigrant children are told to learn English and leave their native language at home, their native-born peers take classes in Spanish, French, Japanese, and other languages that might give them a leg up in their future careers.

Many school districts in Massachusetts designed programs for these more privileged families, according to Phyllis Hardy, executive director of the Multistate Association for Bilingual Education, Northeast, but she said a growing number are joining Boston in using dual language education as a way to better serve immigrant students.

Still, students with disabilities are routinely left out.

In Boston, not all students with disabilities are barred from the dual language programs, but they are severely underrepresented. While 20 percent of students districtwide receive special education services, their numbers are far smaller at the bilingual programs: at the Mario Umana Academy and the Rafael Hernández School, the percentage of students with disabilities is in the single digits.

In addition to the outright exclusion of students with more severe disabilities, bilingual education experts say the low representation can be explained by a lack of interest in these programs among families of children with disabilities. Hardy said some do not see dual language programs as an option, either because schools haven’t made it clear special education supports will be offered or because the families have been told English-only instruction is better.

“We’re still breaking down those barriers,’’ Hardy said. “Some parents may say, “My child is going through a lot. I just don’t want to add another layer of challenge to my child.’’

Hardy emphasized, however, that students with disabilities have done just as well in bilingual education programs as in English-only programs.

For López, one of the ironies of the exclusionary policy is that some of the kids denied admission are already on their way to becoming bilingual. Their native language is Spanish, and the English they speak and hear at school all day is their second language. (Researchers have found, perhaps counterintuitively, that bilingual education can be a particularly effective way to help newcomers master English.)

“They are quite capable of participating in the program and making progress if we give them the opportunity,’’ López said.

Experts and state officials did not know of other districts that explicitly bar students with certain disabilities from enrolling in dual language programs. But Paul Aguiar, director of the Massachusetts Department of Elementary and Secondary Education’s Office of Language Acquisition, said his office routinely fields questions from districts about whether they can keep students with disabilities out of such programs. The answer is always no.

“Obviously if you get a kid with severe disabilities, it’s a little tougher, but we have an inclusion model in this state,’’ Aguiar said. That means students with disabilities should be learning and interacting with their general education peers as often as possible— and never excluded from any program outright. Schools are supposed to find ways to get them the extra supports they need without segregating them into isolated classrooms.

Yet Boston maintains 12 categories of special education programs that teach children in “substantially separate’’ classrooms. In a recent district audit, officials from the state Department of Elementary and Secondary Education called this isolation of kids with certain types of disabilities “a long-standing issue’’ that “contributes to a pattern of inequitable access.’’

During the 2018-19 school year, more than twice as many students in Boston Public Schools spent their days in these segregated special education programs as the state average, according to the audit.

This latest criticism from the state prompted the district to commit to increasing the percentage of students with disabilities in inclusive classrooms over the next three years.

One way Cassellius expects to achieve this is with a new special education director: Ethan d’Ablemont Burnes, who took over July 1. As principal of the Joseph P. Manning School in Jamaica Plain, Burnes prioritized inclusion for students with emotional impairments and saw academic gains as a result. He will lead an effort to help other principals dismantle the programs that segregate students with special needs, Cassellius said.

“That understanding of how to turn around a school, how to do inclusion, and do inclusion right, is really going to be beneficial to the district,’’ Cassellius said.

She is asking principals to make these changes, however— not ordering them to do so.

At Sarah Greenwood, school leaders have resisted López’s advocacy for years. The current principal, Camila Hernandez, declined to comment for this story.

At the school, students in the “substantially separate classrooms’’ spend 100 percent of the school day segregated from their peers in general education (at many other schools with the separate classrooms, the students spend at least some time in more mainstream settings). Not only are students kept from participating in the core academic classes, which are bilingual, they spend recess and lunch on their own, along with art and physical education, according to López.

López said he has seen parents take the extreme step of declining special education services entirely to get their children access to the dual language program at Sarah Greenwood. And he has witnessed thriving students get pulled out of the school’s dual language program when diagnosed with a disability.

Perhaps most frustratingly, López said, he has watched successive education leaders in the district and the state allow the civil rights violations to persist.

Cassellius’ plans for improving special education services in the district are a promising start, he said. But he’s not going to stop agitating until his students are sharing lunch rooms, classrooms and every opportunity the school has to offer — with the rest of their peers.

This story was produced by The Hechinger Report, a nonprofit, independent news organization focused on inequality and innovation in education.