Under the Asbestos Hazard Emergency Response Act (AHERA), what is meant by the phrase "at approximately the same time" in 40 CFR part 763.90(i)(6) as it relates to transmission electron microscopy (TEM) clearance?

The intent of 40 CFR part 763.90(i)(6) is to prevent a local education agency (LEA) from avoiding the TEM air clearance requirement by either artificially dividing up a larger project, or by removing asbestos-containing building material (ACBM) in stages over the course of a relatively short period of time in connection with what normally would have been one large project. For example, if an LEA removed 160 square feet of surfacing ACBM in October and 160 square feet of adjacent surfacing ACBM a few weeks later, the Environmental Protection Agency (EPA) would consider this to be removing contiguous portions of ACBM at “approximately the same time.” Thus, TEM would be required.