美国环境保护局扭转了对自己的法规的长期解释，已向其地区办事处和各州发布了“指导”，并就其根据《联邦清洁空气法案》制定设施建设的空气污染许可规则寻求公众评论。。

The guidance, sent March 25, would allow work to begin on major projects that would be new stationary air pollution sources—such as power plants, industrial boilers and manufacturing facilities, or modifications to those—before obtaining preconstruction permits required under the federal law's New Source Review program.

That program is a set of regulations under the law to protect public health and the environment from air pollution when major new air emissions sources are built or modified.

Most states administer their own programs under the law, but some are EPA-managed, according to the program website.

行业组织和建筑公司说环保局的draft guidance would enable projects on tight timelines to move forward in a timely manner, particularly those that are non-controversial.

In the guidance document released by Anne Idsal, EPA principal deputy assistant administrator, the agency asserts that earlier interpretations of its regulations were too narrow, impeding source owners or operators from starting any construction activity on a project site.

Idsal's new guidance contends that in the past, EPA has considered “almost every physical on-site construction activity that is of a permanent nature to constitute the beginning of ‘actual construction.’”

Industry groups have chaffed under that interpretation, saying it is overly restrictive and prevents projects on a tight timeline from moving forward expeditiously.

In her new guidance to clean-air administrators, Idsal said the policy change is not subject to the normal public notice and comment period associated with a new rule. But EPA is allowing public comment on this through May 11.

As the guidance document is non-binding, however, state air administrators that oversee construction permitting have significant latitude as to whether they must follow it.

环境团体认为，政策变更只是特朗普政府采取的一系列行动中的最新动作，以撤销NSR施工许可计划下的重要环境保护。

The Harvard Environmental and Energy Law Program says that since 2017, EPA has issued notices, memoranda, guidance and letters that narrowed the definition of what “sources” are, limited pollution considered during the NSR review process, and did not enforce the program consistently. The Harvard program equates this to a near dismantling of the program.

The new proposed guidance will allow construction to begin—even on structures that are costly and potentially difficult to remove—as long as no work starts on an actual emissions unit.

EPA adds that any owner that begins construction on a project without a permit does so at its own risk.

Mike Rinkol, environmental services lead at Overland Park, Kan.-based Black & Veatch, says some projects would benefit from EPA’s proposed approach. “On certain projects, if schedules are really tight, this allows [the contractors] to get on site” and do some preliminary work, he says.

Janet McCabe, former acting assistant administrator for EPA's Office of Air and Radiation during the second Obama administration and now director of Indiana University’s Environmental Resilience Institute, says the new guidance doesn’t consider that “if a company has already sunk a lot of capital into a project, it’s very hard [for a permit authority] to say no to a permit.

此外,一旦基础and permanent structures begin to be put in place, technologies available for emissions control may be more limited.

麦凯布说，实施清洁空气法所需的一些最佳可用控制技术可能是不可能的。

“Your options are much more open” before construction begins, she adds.