Middlebury

 

5. Special Precautions for Particularly Hazardous Chemicals.

 

The use of certain chemicals and operations may pose unusual hazards. This includes work with highly toxic materials, reproductive toxins, and select carcinogens, as such materials are defined in 29 CFR 1910.1200 Appendices A and B, and in 29 CFR 1910.1450; and also would include such operations as high-pressure reactions. The degree of the hazard will depend on the quantities of substances involved as well as the duration for which personnel may be exposed, and determination of the actual level of hazard requires informed judgment on the part of the supervisor as well as the laboratory worker. Work of a particularly hazardous nature may be undertaken only with prior approval from the supervisor. If there is a reasonable possibility that individuals other than the person performing the operation may be exposed or affected, The supervisor must provide written or e-mail notice to the Chemical Hygiene Officer regarding the location and duration of the activity. The following conditions also apply:

5.1 General Procedures for Work with Chemicals of Moderate to High Toxicity

All work with toxic chemicals that may expose the user to toxic vapors or respirable dusts shall be performed in an operating fume hood, glove box, vacuum line, or similar device, which shall be equipped as necessary with suitable filters and/or traps.

Determination of appropriate containment devices and personal protective equipment shall be made by the supervisor after consulting appropriate references and the CHO.

At a minimum, splash goggles, gloves suitable for the hazard involved, and a long-sleeved lab coat shall be worn. Hands and arms shall be washed immediately after working with such chemicals.

Signs are to be posted at the work area identifying the hazardous material in use.

The work area is to be thoroughly cleaned and/or decontaminated after use.

5.2 Work with Formaldehyde

Formaldehyde is a select carcinogen and is also an irritant and a sensitizer. The actual degree of hazard will depend on the vapor concentration and length of time that the user is exposed. The precautions below are based on work that may involve exposure to significant airborne or aqueous concentrations of formaldehyde.

Personnel may only be exposed to airborne concentrations of formaldehyde that do not exceed 0.75 ppm calculated as an 8-hour time-weighted average (TWA) or 2 ppm calculated as a 15 minute short-term exposure limit (STEL). If airborne concentrations are likely to exceed 0.5 ppm calculated as an 8-hour TWA, actual concentrations must be monitored.

The best way to reduce airborne concentrations is with appropriate exhaust ventilation; either a fume hood or local exhaust ventilation.

Work with formaldehyde gas or with formalin solutions at concentrations greater than 10% is to be performed in a fume hood or glove box.

Wear splash goggles, gloves, and a long-sleeved lab coat.

Post the work area with a sign indicating that formaldehyde is in use.

Small quantities (a few mL) of formaldehyde waste solutions may be flushed to the sewer with large amounts of water. Larger amounts are to be accumulated as hazardous waste.

5.3 Work with Highly-Toxic Chemicals

Prior approval from the supervisor must be obtained for work with these chemicals.

The user will design the experiment such that the smallest amount of chemical that is consistent with the desired outcome is obtained and utilized.

The supervisor shall ensure that a written protocol is in place that describes in detail the work to be performed, the chemicals to be used, any other hazards that may be involved, and the protective measures that will be taken.

All work with toxic chemicals that may expose the user or other individuals to toxic vapors or respirable dusts shall be performed in an operating fume hood, glove box, vacuum line, or similar device, which shall be equipped as necessary with HEPA or other suitable filters and traps.

Determination of appropriate containment devices and personal protective equipment shall be made by the supervisor after consulting appropriate references and the CHO.

At a minimum, splash goggles, gloves suitable for the hazard involved, and a long-sleeved lab coat shall be worn. Hands and arms shall be washed immediately after working with such chemicals.

Two people must always be present during any work with highly-toxic chemicals.

A designated work area, consisting of a hood, glove box, portion of a laboratory, or an entire laboratory room as necessary, shall be established for work with these substances.

The designated work area shall be posted with signs identifying the hazardous material in use, and the boundaries of the work area shall be clearly marked.

Only those persons trained to work with the chemicals may be allowed in the designated area.

The work area is to be thoroughly cleaned and/or decontaminated after use.

5.4 Prior Approval for Hazardous Operations

Certain operations may pose unusual hazards, such as high-pressure reactions; work with highly reactive materials; and the like. Requests to perform such work require the supervisor’s approval, and the Chemical Hygiene Officer must be notified in writing or via e-mail about the scope and duration of the operation.