What is the safest course of action if you just heard that one of your crew mixed up a large batch of epoxy and accidentally left it in a pail in bulk long past its pot life?
He's asking what to do about the boiling, spitting and smoking mixture which can reach temperatures in excess of 350 °F. In some cases, the epoxy mixture can become so hot it will self-ignite. If some epoxy products are mixed and left in bulk (not placed in use), an exothermic reaction can occur generating significant heat which can potentially lead to a fire.
If the pail is located inside a building, try to locate a bag of sand, then make sure that your guy has the proper OSHA haz mat training and PPE to approach the overheating bucket--there should be no exposed skin. Gradually pour sand in the bucket. The sand dilutes the hot epoxy and also cools the mixture as it adds mass.
Avoid moving the bucket without double checking that the crewman has a face shield, very heavy gloves and preferably 2 layers of protective clothing. It is best to use a properly fitted face mask with organic fume canisters. If the pail is made of plastic and you suspect the material is hotter than 250 °F, it should not be moved by the handle as the plastic has lost much of its strength. If possible, transfer it outside on a pallet with a forklift to minimize the potential for burns. Be careful not to breath any smoke or fumes generated by the mixture.
If the hot container is located outside, you can cool the exterior of the pail with a large fan and/or water and add sand, dirt, aggregate, cat litter or any inert particulate solid material to help cool the mass. Don't add water directly to the epoxy as the mixture of hot epoxy and water may increase the potential for accidental burns. Keep a dry powder fire extinguisher handy just in case.
Epoxy on skin
After some product exposure on the job, your skin itches--now what? Prolonged exposure to most construction chemicals (including epoxies) can result in dermatitis symptoms. The part b (hardener) can be very alkaline and cause burns. The best advice is to protect your skin by wearing long sleeves, long pants, and disposable gloves. Of course, you should double check the product SDS for any additional recommended PPE (don't forget eye protection--safety glasses, goggles or face-mask) that will help safeguard you in the product application. If the project work involves likely repeat exposure, the use of disposal coveralls is a great practice. Avoid breathing the vapors of the part b epoxy hardener components as these can be irritating to your lungs and may exacerbate your exposure. Learn to remove your latex gloves like a surgeon; grab the outside of one glove at the wrist with a couple of fingers and pull it inside out, then use that glove's interior side to pull off the other glove inside out so the chemicals remain on the inside surfaces.
Exposed skin can be protected by a barrier cream such as Gloves in a Bottle (800) 600-1881. Clothing should be cleaned regularly--don't wear the same shirt or pants 3 days in a row. Practice thorough hand scrubbing with a good (but mild) dish-washing soap at every break; avoid cleaning your hands with solvent. Maintain the cleanliness of everything you touch including: door handles, tools, product containers, benches and seats, steering wheel, ladders, and commonly used equipment. Keep a supply of paper towels and/or clean rags so you're not spreading a thin film of chemicals with every swipe. Don't eat or drink in the area where the products are being used. Minor irritations can be treated with cortisone cream. In the event your pants or shirt become contaminated (but you didn't notice until several hours later), the best practice is to remove the article of clothing and flush the area of skin for 10-15 minutes in cold water following by a soapy water rinse. Do not use solvents on your skin. For severe exposure cases, visit the nearest urgent care or ER immediately.
Epoxy in the air
After repeated exposure to epoxies (and other construction chemicals), some people can become sensitized. This sensitization can occur through contact between epoxy and the skin but also through the lungs. An severe allergic reaction including hives and potentially difficult breathing is possible in very sensitized individuals. To prevent sensitization, insist on good ventilation and air exchange in closed environments when mixing, applying and sanding or grinding epoxies. If necessary, wear a mask with organic chemical filters during mixing or sanding activities especially in closed environments. A critical step is to always practice careful personal hygiene during work exposure periods.
Always have on hand a 3 ring binder with hard copies of all of the SDSs for every product used on the job-site. A good internet connection can't be assumed and it's possible in an emergency, it may be difficult to locate the treatment information in a timely fashion. Do save the ChemTrec number (1-800-262-8200) and the associated local number on all cell phones in case all else fails as they have most SDS sheets on file.