There's also the caustic chemicals used in the Wet-cleaning business. From /v/pizzagate:

Dhs.CON.N.E.B appears to be Saudi Arabian owned, this means the entire block both sides the street was bought by SAUDIA ARABIA and given to Friend's Andrew Kline for FREE in 2003
Now we're finding out that almost all of these are tied to andrew kline and not 5021 can do corpse-disposal with caustics and drainage, and 5029 is besta-pizza Conneb II LLC, H Gill & Son - sold all on 2003, for $0 ( zero dollars )
5013 = CVS Pharmacy and Moneygram
5015 = Politics & Prose and The Den Coffeehouse and Wine Bar
5019 = Sheffields Wine & Liquors
5020 = Exxon Gas Station
5021 = Regal Custom Wet Cleaners
5029 = Besta Pizza
5031 = Bucks Camping & Fishing
5035 = Little Red Fox
5037 = Comet Ping Pong