Is a safety officer a must essential for every Construction site, Industry, Oil and Gas Sector?

depends on the maturity level of the company's safety culture ..

for companies that have been matured and safety is being integrated with their activities, safety office is no longer required. Their nature supervisor responsible to manage, monitor and control their safety implementation. in this level, safety officer will only be source of knowledge or to ensure the compliance.

this concept a OHSMS concept to create safe place - safe person and also safe system 

Safety officer for management of Safety and Security of an organization or site or factory:

1.     A safety officer or someone assigned to look after safety and security is always needed in in organization. Normally, in medium size offices, Facility Management Manager or Administrative Manager looks after safety and security of the staff. However, in large companies with more than “1000” people or so, a designed Safety Officer/Manager is absolutely essential.

2.     Specific qualification is not mandatory but some essential skills are: (a) to understand the situation quickly and respond very quickly. (b)Must have knowledge on Fire safety installations, emergency evacuations, CCTV, Access Control and Staff Security Management.

3.     A Safety Officer must organize and handle all the operations during emergency period like fire hazard, emergency evacuation and also remain responsible for effective operation and maintenance of all security related installations

4.     Depending upon the number of people in the company or  and complexity of operations, the Management shall decide the number of people required in Safety Department

Absolutely Yes. To ensure avoidance of the possible hazards at site.

• Why needed  safety officer for any organization? 

To ensure avoidance of the possible hazards on site

• What requirements needed to work as a safety officer?

Knowledge on the field and training

• How a safety officer given best service for his organization?

Making sure that there will be no incidents and accidents on site. Making the site organize and clean.

• How many safety person needed for medium and large organization and what will be categorizes ( Example: Safety Officer, Safety Supervisor, Safety Manager or First Aid ) ?

Safety Officer = 50 workers

Safety Supervisor = 200 Workers

Safety Manager = 300 Workers

First aid = 50 workers

It definitely is a must to ensure someone is making sure that all humans on site are working safely and that there is no potential for accidents or injury to the humans. It is not a must to have someone to do that however someone should be observing these things at all times!I do not know about the law, it also could be that by law you must have a safety officer. 

A safety officer is mandatory requirement for construction industry regardless of nature of job.

According to HSE and CDM regulations, if an organisation have more then 5 employees than it is mandatory to have a safety officer  

safety officers are important and key not only to the success of the Patient Safety program at any organization, but also to the success of the organization as a whole. Patient safety officers do not need to be clinicians.

• Make the position one of high rank in the organization so the patient safety officer will have the authority to act and remove barriers to change.
• Have regular meetings between the patient safety officer and the chief executive officer.
• Provide educational opportunities to the patient safety officer so he or she can continually seek best practices.
• Ensure that the patient safety officer has the resources and organizational support necessary to implement plans.
• Require the patient safety officer to make regular presentations to the organization’s governing body.
• Choose a clinician who is held in high regard by peers regardless of "rank" — someone who "walks the walk" and not just "talks the talk." While traditional choices might be a physician or nurse, other health care providers such as pharmacists should be considered.
• Patient safety officers are important and key not only to the success of the Patient Safety program at any organization, but also to the success of the organization as a whole. Patient safety officers do not need to be clinicians. The knowledge and skill sets go beyond clinical specialization. Patient safety is about culture, error analysis, and teaching.

Safety officer is badly needed in the construction industry,to lead and guide the people the proper protection equipment to be wear always and to avoid hazard at site.

thank you great answers

i wish to get courses

Definitely.

If their is a work or activity, their is a risk and if their is a risk their is a potential accident and incident that may occur during the course of operation.

Safety department is being setup on the purpose of preventing, protecting and assuring the safety and health of the workforce and environment.