I was certified to do these a few years ago when the appraisal business was slow, and actually did a couple. I really enjoyed them, and they use many of the same skill sets we use as appraisers. You inspect the property for readily observable environmental issues (underground tanks, etc.), do historical record research, interview previous owners and neighbors, etc. The you write a report (usually narrative) and recommend actual further testing (phase II) or state no further testing needed. I stopped doing them for two reasons: 1) There was little demand. In my area, lenders were only ordering Phase I's if the transaction was over 1 million dollars (nobody wanted to pay 1500+ for somehthing that only reduced liabililty and was not required.) and 2) In order to do these you have to be an Environmental Professional. There are several ways to be classified as an EP. I can't remember the specifics but like a licensed engineer or geologist or ten years training/experience. As T said, basically two sets of standards: ASTM and AII (all appropriate inquiry thru EPA.) One (cant remember which) required the EP to actually physically inspect and the other said he must supervise. So you must have an EP to sign your reports. Later found out that many in the industry frown upon having an non EP inspect and an EP sign off as supervisor (think trainees with appraiser sitting at office signing everything.) If the class is not expensive, you would probably find it interesting. And if you can find an EP, you may even want to pursue. Re Rex's comment, you absolutely need insurance. My EP had a 1 or 2 million dollar environmental coverage policy. There is also an abbreviated site inspection called a transaction screen that lenders sometimes use. There are no specific requirments to do these, I dont think. Google phase 1 environmental assessments and a bunc of sites come up explaining; also the ASTM site is good, as is a site for a company called EDR that provides the historical reports.