General Life-Threatening Hazards

Water protection

A Coast Guard-approved life jacket or buoyant work vest should be used if there is danger of falling into water while working. For emergency rescue operations, boats and ring buoys with at least 90 feet of line must be provided.

Visibility

Night workers and flagmen who might be struck by moving vehicles need suits or vests designed to reflect light.

Lifelines and safety nets

In jobs involving potential fall hazards, lifelines, body harnesses, and/or lanyards must be used. If lifelines are used where they might be cut accidentally, they should be padded or otherwise protected. Rope should have a strength of 5,400 pounds. Lifelines should be inspected regularly to assure their perfect condition.

Lanyards should be of at least 1/2-inch nylon or the equivalent and should be short enough to allow a fall no greater than six feet. They must be firmly secured above the working surface. Body harnesses are required for personal fall arrest systems.

Nets should be used when a lifeline or a body harness is not practical. Forged steel, safety hooks, or shackles should be used to fasten a net to its supports. The mesh should be no larger than 6″ x 6″ and the nets should extend beyond the edge of the work surface. Safety nets must be tested to ensure that they are tight enough to prevent an employee from making contact with any surface or structure below.

Heat stress

Wearing PPE puts a worker at considerable risk of developing heat stress. This can result in health effects ranging from transient heat fatigue to serious illness or death. Heat stress is caused by a number of interacting factors, including environmental conditions, clothing, workload, and the individual characteristics of the worker.

Individuals vary in their susceptibility to heat stress. Factors that may predispose someone to heat stress include:

• Lack of physical fitness, lack of acclimatization, age,
• Dehydration, obesity, substance abuse, infection,
• Sunburn, diarrhea, and chronic disease.

Reduced work tolerance and the increased risk of excessive heat stress is directly influenced by the amount and type of PPE worn. PPE adds weight and bulk, severely reduces the body’s access to normal heat exchange mechanisms (evaporation, convection, and radiation), and increases energy expenditure.

When selecting PPE, each item’s benefit should be carefully evaluated in relation to its potential for increasing the risk of heat stress. Once PPE is selected, the safe duration of work/rest periods should be determined based on the:

• Anticipated work rate,
• Ambient temperature and other environmental factors,
• Type of protective ensemble, and
• Individual worker characteristics and fitness.

Physical condition

Physical fitness is a major factor influencing a person’s ability to perform work under heat stress. The more fit someone is, the more work he/she can safely perform.

At a given level of work, a fit person, relative to an unfit person, will have:

• Less physiological strain;
• A lower heart rate;
• A lower body temperature, which indicates less retained body heat (a rise in internal temperature precipitates heat injury);
• A more efficient sweating mechanism;
• Slightly lower oxygen consumption; and
• Slightly lower carbon dioxide production.

Level of acclimatization

The degree to which a worker’s body has physiologically adjusted or acclimatized to working under hot conditions affects his or her ability to do work. Acclimatized individuals generally have lower heart rates and body temperatures than unacclimatized individuals, and sweat sooner and more profusely.

This enables them to maintain lower skin and body temperatures at a given level of environmental heat and work loads than unacclimatized workers. Sweat composition also becomes more dilute with acclimatization, which reduces bone loss.