It's always wise not to take all reporting at face value, and to look at the underlying documentation. In this instance, the BPDA staff report.
https://www.universalhub.com/files/parcelm.pdf
In which we learn, that the salt company is already leasing the larger parcel associated with the North Jetty from Massport, and has committed to spending $30 million to improve berthing space at the North Jetty in conjunction with that lease. The BPDA parcel, Parcel M, is the smaller of the parcels, and the salt company proposes to spend $3.5 million in improvements to this parcel.
There were previous solicitations for the BPDA-owned parcel, without a successful bid. The three bids for the current round were 1.) a company wanting to use an existing building on the site as a training school for glaziers (rejected as a non-maritime use); 2.) a company proposing to construct a large warehouse for DHL, the logistics company; and 3.) the salt company.
The salt company expects to use the Massport parcel for salt storage, not the BPDA parcel.
This is a link to Google Streetview of Parcel M, and the existing building on the site, currently used by several city departments.
https://goo.gl/maps/nwyEttk7AfPrGozm8
This is Streetview link to Massport parcels 7 and 8, where the salt company will spend $30 million to allow deep draft ships to dock at the North Jetty. The small warehouse will be retained and renovated.
https://goo.gl/maps/FgeUX4qhp5ZBB2Jv9