By CBS3 Staff

PHILADELPHIA (CBS) — Classes start next week for Masterman School students, but teachers refuse to prepare their coursework inside after concerns about asbestos.

On Thursday, educators protested outside the building, working on laptops in sweltering heat. They spent all day outside as a message against a harmful work environment.

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“We’re talking about asbestos and harmful chemicals that if they aren’t abated carefully can cause harm,” teacher Elizabeth Diffenderfer told CBS3.

Cameras rolled as the district’s chief of schools arrived, scolding the teachers; Evelyn Nunez told them their protest was considered an unauthorized absence. Nunez threatened to dock a day of pay.

That didn’t stop the group from demanding transparency on what exactly is in their place of work. Their concerns also include the presence of lead and mold.

Math teacher Ethan Tannen has specific requests when it comes to getting all the details.

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“Given the inspector general’s report on the districts handling of the Ben Franklin incident, we cannot give them the benefit of the doubt,” he said.

Superintended William Hite told Eyewitness News the frustrations are based on incomplete information.

“Abatement and repairs were made in January, July and august of this year which addressed the 60 areas of damaged asbestos,” Dr Hite said. “All the work was conducted under the supervision of a 3rd party certified asbestos project inspector.”

Parent groups, as well as the Philadelphia Federation of Teachers, want scientists to conduct a joint inspection.

The union will not comment on whether they will combat the district docking teachers’ pay for Thursday’s demonstration.

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CBS3’s Alecia Reid contributed to this report.