To continue on the subject of the last post, let’s assume that you disposed of the tank and the pea gravel or sand that surrounded the tank without incident. You even excavated as much of the stained soil from the base of the excavation as possible while you had the excavation contractor onsite. Let’s also assume that you were able to back-fill the excavation with 1 sac slurry without incident. The soil samples you collected from the base of the excavation came back with gasoline and BTEX, so you will have to perform an additional investigation under the direction of the County Fire Department. You’ve hired your drilling contractor to come out and collect some soil samples as well as install some vapor extraction wells.
You may be thinking to yourself, “I am starting to not understand these terms”. That’s completely fine. Let me take a minute to define a few of these terms before we move on:
BTEX – A combination of volatile organic compounds commonly found in gasoline, Benzene, Tolulene, Ethylbenzene, and Xylenes. Xylenes inlcude m,p-xylenes, o-xylenes, and total xylenes. These compounds all have their own regulatory limits, there is no regulatory limit for BTEX as a group.
Clean Certificate – A Marine Chemist will certify the tank for “Hot Work”. If “Hot Work” will be done on the tank at the destination it will be transported to, the certification that the tank is clean and vapor free should be performed by a certified Marine Chemist.
CUPA – Certified Unified Program Agency, a California state agency. The CUPA was created by SB 1082 in 1994 to consolidate a number of hazardous material programs into one single agency. In many areas the local CUPA is the local fire department, but based on where your property is located your CUPA may be a city agency, the department of health services, or the local arm of the Environmental Protection Agency. In the previous post, the CUPA agency is the Los Angeles countyHot Work – Welding or cutting of metal with a torch.
Marine Chemist – A person qualified to certify a tank as “clean” meaning that all visible deposits, sludge, and all other foreign materials have been removed from the inside of the tank and that there is no flammable hazard or vapors exist. The Marine Chemist fills out the “Clean Certificate”.
One Sack Slurry – A type of cement mix that is delivered in a cement truck. It is mixed at the cement plant and consists of one sack of portland cement to one sack of aggregate, in this case we usually use medium sand. The benefits of a one sack slurry is that is has a pretty good compressive strength meaning that you can drive a truck over it and once it is dry and it can still be worked with an excavator or a backhoe.
Pea Gravel – Gravel, usually crushed granite, that falls within a certain size range that roughly equals the size of a pea. This type of gravel, sand, or one-inch crushed rock is used when a UST is installed because it doesn’t settle or allow the tank to shift around inside the tank pit.
UST – Underground Storage Tank, usually used to hold petroleum hydrocarbons such as gasoline or diesel. Can also be used to hold industrial chemicals and waste oil.
That is a good ammout of information for this post, so I’ll end it there. Next time we’ll discuss what is involved with investigating the extent of the imacts from this leaking tank.