Whether you need a Phase II ESA or not depends on a number of factors. To begin with, you will not need a Phase II ESA if you haven't done a Phase I ESA. Phase II ESAs are only applicable when the Phase I ESA uncovers potential recognized environmental conditions (REC) or contamination in your property and requires further investigation to confirm the presence or absence of threats.
Let's say you have done a Phase I ESA and the findings didn't recognize any potential threats. In this case, you don't need to go for Phase II ESA and the Phase I ESA will be the end of things.
Now let's assume the Phase I ESA report comes back with a chance of contamination. You then have to confirm the presence of the contaminants through further testing as Phase I ESAs don't involve any digging or evaluation of samples for contamination. Thus we can say that Phase II ESAs are based on the findings of the Phase I ESA and provides a more varied and comprehensive analysis.
For example, Phase II ESAs can include the surficial and sub-surficial soil analysis, groundwater assessment, indoor air sampling and more to supplement the findings of Phase I ESA.
It's safe to say that all Phase I ESAs don't lead to Phase II ESAs. You should be cautious if anyone says otherwise because they might just want to steer you in the wrong direction and milk you for more money. That's also the reason why some firms offer Phase I ESA at dirt cheap prices and always tag along Phase II ESA with their service. You should remember that a Phase II ESA is only required if the prior assessment reveals potential threats or environmental hazards.
You should always go for an honest and reliable firm for all your environmental due diligence needs. We are always clear about our approach and never adopt dishonest ways to game our clients. Even though it's not necessary, you are free to go for Phase II ESA if you find it important to establish the safety of your property. It's completely your call!