More than nine out of every ten employees at the Environmental Protection Agency (EPA) are considered “non-essential” and have been furloughed in the federal government’s shutdown.

Reuters obtained an EPA guidance in which the agency said it would “classify 1,069 employees, out of 16,205, as essential,” which is about 6.6% of the agency’s workforce, in the event of a government shutdown, which occurred on Tuesday.

The guidance also reportedly said that “most workers at the Office of Air and Radiation, which is in charge of writing and implementing most of the EPA’s major air pollution rules,” would be furloughed, which will tighten the various deadlines facing the agency.