surfaces should also be easy to decontaminate or covered with appropriate protective material, which can be properly disposed of when the procedure is complete. Mixtures that contain toxic chemicals or substances of unknown toxicity must never be smelled or tasted.

6.   Carefully plan the transportation of very toxic chemicals. Handling these materials outside the specially designated laboratory area should be minimized. When these materials are transported, the transporter should wear the full complement of PPE appropriate to the chemicals and the type of shipping containers being transported. Samples should be carried in unbreakable secondary containment. (See Chapter 5 for more information about transporting laboratory chemicals.)

6.D.6 Preparing for Accidents with and Spills of Substances of High Toxicity

Be sure that emergency response procedures cover highly toxic substances. Spill control and appropriate emergency response kits should be nearby, and laboratory personnel should be trained in their proper use. These kits should be marked, contained, and sealed to avoid contamination and to be accessible in an emergency. Essential contents include spill control absorbents, impermeable surface covers (to prevent the spread of contamination while conducting emergency response), warning signs, emergency barriers, first-aid supplies, and antidotes. Before starting experiments, the kit contents should be validated. Safety showers, eyewash units, and fire extinguishers should be readily available nearby. Self-contained impermeable suits, a self-contained breathing apparatus, and cartridge respirators may also be appropriate for spill response preparedness, depending on the physical properties and toxicity of the materials being used (see section 6.C.2.4).

Experiments conducted with highly toxic chemicals should be carried out in work areas designed to contain accidental releases (see also section 6.D.3). Trays and other types of secondary containment should be used to contain inadvertent spills. Careful technique must be observed to minimize the potential for spills and releases.

Prior to work, all toxicity and emergency response information should be posted outside the immediate area to ensure accessibility in emergencies. All laboratory personnel who could potentially be exposed must be properly trained on the appropriate response in the event of an emergency. Conducting occasional emergency response drills is always a good idea. Such dry runs may involve medical personnel as well as emergency cleanup crews.

(See also sections 6.C.10.5 and 6.C.10.6)

6.D.7 Storage and Waste Disposal

Use unbreakable secondary containment for the storage of highly toxic chemicals. If the materials are volatile (or could react with moisture or air to form volatile toxic compounds), containers should be in a ventilated storage area. All containers of highly toxic chemicals should be clearly labeled with chemical composition, known hazards, and warnings for handling. Chemicals that can combine to make highly toxic materials (e.g., acids and inorganic cyanides, which can generate hydrogen cyanide) should not be stored in the same secondary containment. A list of highly toxic compounds, their locations, and contingency plans for dealing with spills should be displayed prominently at any storage facility. Highly toxic chemicals that have a limited shelf life need to be tracked and monitored for deterioration in the storage facility. Those that require refrigeration should be stored in a ventilated refrigeration facility.

Procedures for disposal of highly toxic materials should be established before experiments begin, preferably before the chemicals are ordered. The procedures should address methods for decontamination of all laboratory equipment that comes into contact with highly toxic chemicals. Waste should be accumulated in clearly labeled impervious containers that are stored in unbreakable secondary containment. Volatile or reactive waste must always be covered to minimize release.

Follow procedures established by the institution’s EHS experts for commercial waste disposal. Alternatively, consider the possibility of pretreatment of waste either before or during accumulation. In-laboratory destruction may be the safest and most effective way of dealing with waste, but regulatory requirements may affect this decision.

(For further information about disposal of hazardous waste, see Chapter 8. For information about regulatory requirements, see Chapter 11.)

6.D.8 Multihazardous Materials

Some highly toxic materials present additional hazards because of their flammability (see Chapter 4, section 4.D.1, and Chapter 6, section 6.F), volatility (see sections 6.F and 6.G.6), explosivity (see Chapter 4, section 4.D.3; see also section 6.G.4), or reactivity (see Chapter 4, section 4.D.2; see also section 6.G.2). These materials warrant special attention to ensure that risks are minimized and that plans to deal effectively with all potential hazards and emergency response are implemented. (Table 5.1 provides information regarding incompatible chemicals and substances requiring extreme caution.)



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