(JTA) — Fifty-two people — former yeshiva students, parents of current yeshiva students and former teachers from schools — reportedly signed a letter sent to New York City education officials expressing “deep concern” about “the poor quality and scant amount of secular education” at the 39 schools with which they say they are affiliated.

The letter, sent to seven district superintendents in Queens and Brooklyn and New York City Schools Chancellor Carmen Farina, allege that the yeshivas are failing to meet New York state law requiring all nonpublic schools to provide an education that is “substantially equivalent” to what is offered in public schools. The letter urges the superintendents to “investigate the quality of secular education and, in particular English instruction, at the listed Yeshivas and to take steps to ensure that pupils at these Yeshivas receive the essential and substantially equivalent education to which they are entitled.”

The letter-writing campaign was organized by Yaffed, a 3-year-old advocacy group that seeks to improve the quality of secular education in haredi Orthodox schools in New York state. Haredi Orthodox schools devote far greater time and resources to religious instruction than to secular instruction, particularly in boys’ schools. As a result, some graduates complain that they are unprepared for careers and unable to support themselves financially.

Yaffed shared a copy of the letter in a news release, but is withholding the names of the signatories and is asking the letter’s recipients not to release them in order to protect the letter-writers’ “safety.” The group also did not release the names of the 39 schools it said were identified in the letter.