Falling Hazards
The most common injuries workers suffer from falling objects are bruises, fractures, strains, and sprains. The objects that commonly fall range from large items such as roof trusses and steel beams to small items such as fasteners and small hand tools.

Introduction:
Hand tools include a wide variety of non-powered devices such as wrenches, pliers, hammers, and screwdrivers. These tools may seem harmless, but they are the cause of many injuries. The following is a summary of safety practices related to hand tools. General Hazards:
• The two most common hazards associated with the use of hand tools are misuse and improper maintenance.
• Misuse occurs when a hand tool is used for something other than its intended purpose. (An example would be using a screwdriver as a chisel. This may cause the tip to break and strike someone).
• Improper maintenance allows hand tools to deteriorate into an unsafe condition. (Examples would include cracked wooden handles that allow the tool head to fly off or mushroomed heads that can shatter upon impact).
• Specially designed tools may be needed in hazardous environments. (Always use non-sparking tools in the presence of flammable vapors or dusts. Insulated tools with appropriate ratings must be used for electrical work).

Cause of health hazards
· Static load

Static load or effort occurs when muscles are kept tense and motionless. Examples of static effort include holding the arms elevated (Figure 1a), or extended forwards or sideways (Figure 1b). (Try holding your arm straight out in front of you for a few minutes and you will see what we mean. Put any object in your outstretched hand and its weight will add to the static effort exponentially.) Bending and twisting the neck or the whole torso can also increase static load considerably. Add the exertion of force required by hand tools, and static load can increase still further (Figure 1c).
Static effort, that is holding any strained position for a period of time, is a particularly undesirable component in any work situation. Static effort increases the pressure on both the muscles, as well as on tissues, tendons and ligaments. It also reduces blood flow which cause a localized fatigue at a much quicker rate than would be expected by performing dynamic work (involving movement). Statically loaded muscles are much more vulnerable to fatigue and subsequent injury than muscles which are performing dynamic work. Furthermore, muscles which are tired by static work take more than 10 times longer to recover from fatigue.
· Awkward postures:

Awkward postures are body positions that are uncomfortable, or put the body parts in use in a mechanical disadvantage. Muscles and joints work most efficiently in specific positions, usually at the midpoint of the joint's range of movement. When muscles are working at the same time as they are being stretched, they are more susceptible to injury.
Awkward postures refer to positions of the body (limbs, joints, back) that deviate significantly from the neutral position while job tasks are being performed.

When employees are performing tasks that involve long reaches they are exposed to extreme awkward postures; that is, the positions of their shoulders, elbows and/or back deviate significantly from more neutral positions. Repeatedly performing tasks in such positions poses increased stress on the joints and/or spinal discs.

As mentioned before, muscles do not work as efficiently in awkward postures, and the muscles must exert more physical effort to accomplish the task. This increased force contributes to muscle-tendon fatigue and strain. For example, the shoulder may deviate at least 90 from its neutral position when reaching across a conveyor to grasp an object.

If the employee continues doing such reaches, the stress on the muscles and tendons in the shoulder can cause irritation and inflammation of the tendons and shoulder joint. This, in turn, may place increased pressure on nerves and blood vessels, reducing the supply of blood to the affected muscles and tendons.
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When the hand holds and uses a tool in an awkward position it has less strength and is consequently more susceptible to soreness and eventual injury. If the arm is uncomfortable, the rest of the body is likely to be so as well, because it is natural to compensate for discomfort by trying to re-align the body by bending the back, rounding the shoulders, tilting the neck, and so on.

Awkward positions of the upper body considerably increase the effort needed to complete the task. The resulting fatigue, discomfort, and pain add further to the risk for developing injury.

· Tissue compression from forceful grips

As a rule, using a hand tool requires a firm grip. The resulting compression of soft tissue in the palm and fingers may obstruct blood circulation, resulting in numbness and tingling. Blisters are also common due to friction between the palm of the hand and the handle of the tool.
· Vibration:

The blood supply to vibrating areas of the body is reduced, which reduces the ability of the muscles to contract and leads to more rapid fatigue. Whole body vibration is experienced by operators of vehicles, particularly heavy vehicles. Hand-arm vibration occurs in workers using vibrating or impact tools such as rattle guns, drills or hammers.
The only effective way to reduce vibration in power tools is at the design stage. This fact makes tool selection most critical. The common practices of covering handles of vibrating tools with a layer of viscoelastic material or of using anti-vibration gloves made of similar material are of dubious value. These "anti-vibration" materials will dampen vibration above certain frequencies that are characteristic for the kind of material, but most of the vibration energy in a handle of a power tool is below those frequencies.