structural tests, then containers are filled with food and left in the cages of captive black bears in a zoo in California. If the canister survives the zoo test, it is then conditionally approved. Full approval is only given after three months' successful field tests by users. The (IGBC) first conducts a visual inspection to identify products that may be harmful to humans or the captive test bears. Next, food such as peanut butter, fish, or other attractant will be placed inside the container. This container will then be put in the grizzly bear enclosure at The Grizzly & Wold Discovery Center in West Yellowstone Montana. To pass the IGBC certification, a bear must have a total of one hour of direct contact with the product, not counting licking. The product must remain functional and have no penetrations larger than 1/4 inch. It is recommended that canisters be left on the ground, at least 100 feet/30 metres from the campsite. Suspending the canister can allow the bear to smash it to the ground or use the suspension gear to carry it away. Most canisters are designed to resist clawing and biting from bears rather than loaded drops from trees or cliffs. To prevent a bear from rolling it away, a hiker can leave the container in a bush, a shallow depression, or wedged between rocks or logs. Placing the canister near water could allow the container to float away. Reflective tape and labelling the container helps in recovery. Bear bagging An alternative is bear bagging, also called bear hanging or bear hangs, wherein items attractive to a bear such as food, toiletries, or other scented items are placed in a bag and then raised into the air with a rope — out of its reach. The rationale is that bears, being unable to reach the food, are less drawn to campsites and pose less of a threat to campers and their equipment. Often this is done by tying another length of rope tightly between two trees or other tall objects. A bear bag should be at least 15 feet (4.5 m) high and 10 feet (3 m) from any vertical support. The counterbalance method, Marrison system, and Pacific Crest Trail method are a few different techniques to use when hanging a bear bag. In recent years, bear bagging has received significant scrutiny for its ineffectiveness. In alpine environments there are