is used to locate chemicals for use or sharing in the laboratory, even a moderate degree of inaccuracy erodes confidence in the system and discourages use. The need for high fidelity of data is greater for a tracking system, because trained laboratory personnel will rely on it to save time locating chemicals rather than physically searching. For these reasons, appropriate measures should be taken periodically to purge any inventory or tracking system of inaccurate data. A physical inventory of chemicals stored, verification of the data on each item, and reconciliation of differences are performed annually. This procedure coincides with an effort to identify unneeded, outdated, or deteriorated chemicals and to arrange for their disposal. The following guidelines for culling inventory may be helpful:
• Consider disposing of materials not expected to be used within a reasonable period, for example, 2 years. For stable, relatively nonhazardous substances with indefinite shelf lives, a decision to retain them in storage should take into account their economic value, scarcity, availability, and storage costs.
• Make sure that deteriorating containers or containers in which evidence of a chemical change in the contents is apparent are inspected and handled by someone experienced in the possible hazards inherent in such situations.
• Dispose of or recycle chemicals before the expiration date on the container.
• Replace deteriorating labels before information is obscured or lost to ensure traceability and appropriate storage and disposal of the chemicals.
• Because many odoriferous substances make their presence known despite all efforts to contain them, aggressively purge such items from storage and inventory.
• Aggressively cull the inventory of chemicals that require storage at reduced temperature in environmental rooms or refrigerators. Because these chemicals may include air- and moisture-sensitive materials, they are especially prone to problems that are exacerbated by the effects of condensation.
• Dispose of all hazardous chemicals at the completion of the laboratory professional’s tenure or transfer to another laboratory. The institution’s cleanup policy for departing laboratory researchers and students should be enforced strictly to avoid abandoned unknowns that pose unknown hazards to remaining personnel and have high disposal costs.
• Develop and enforce procedures for transfer or disposal of chemicals and other materials when decommissioning laboratories because of renovation or relocation. Try to avoid receiving entire chemical inventories from decommissioned laboratories and do not donate entire chemical inventories to schools or small businesses.
Chemical inventory challenges have not changed since the first use of index card files. The initial challenge is ensuring that every laboratory chemical gets entered into the inventory. This task often requires the concerted effort of many staff members. The second challenge is keeping the inventory current. Meeting this challenge usually requires designating one or more responsible individuals to enter new materials into the system; these individuals are the only personnel who should have write/edit access to the inventory. Facility procedures must make sure that notice of all new materials is presented to these designated individuals for entry into the inventory. Assuming that every staff member will faithfully enter new chemicals into the system results in an obsolete inventory. A third challenge is making sure that consumed chemicals, that is, empty containers, are removed from the active inventory.
Inventories are valuable to laboratory operations if everyone supports and contributes to the inventory. Managers with budgetary responsibilities appreciate the value of an established inventory system in reducing procurement and operating costs. Laboratory waste coordinators favor more efficient use of in-house materials resulting in reduced quantities of waste.
5.D.2 Exchange of Chemicals Between Laboratories and Stockrooms
The exchange or transfer of chemicals between laboratories at an institution depends on the kind of inventory system and central stockroom facilities in place. Some institutions encourage laboratory personnel to return materials to the central stockroom for redistribution to others. The containers are sealed or open with a portion of the material used. Containers that have been opened are often of sufficient purity to be used as is in many procedures. If the purity is in doubt, the person who returned the material should be consulted. The stockroom personnel can update the central inventory periodically to indicate what is available for exchange or transfer. For an exchange program to be effective, all contributors to and users of the facility must reach a consensus on the standards to be followed concerning the labeling and purity of stored chemicals.
A word of caution is offered in regard to surplus-chemical stockrooms; they must be managed with the same degree of control as a new-chemical storage area.