The Final Rule for Permit-Required Confined Spaces was published in the Federal Register on January 14, 1993, and became effective on April 15, 1993. The standard is based on years of gathering information on confined space fatalities and on testimony about the hazards of confined spaces from all sectors of industry and labor. Because it applies to all of general industry, a performance-oriented standard was developed rather than a specification standard. The rule citation is 29 CFR1910.146.

Many workplaces contain spaces which are considered "confined" because their configurations hinder the activities of any employees who must enter, work in, and exit them. For example, employees who work in process vessels generally must squeeze in and out through narrow openings and perform their tasks while cramped or contorted. For the purposes of this rulemaking, OSHA is using the term "confined space" to describe such spaces.

In addition, there are many instances where employees who work in confined spaces face increased risk of exposure to serious hazards. In some cases, confinement itself poses entrapment hazards. In other cases, confined space work keeps employees closer to hazards, such as asphyxiating atmospheres or the moving parts of a mixer, than they would be otherwise.

OSHA uses the term "permit-required confined space" (permit space) to describe those spaces which both meet the definition of "confined space" and pose health or safety hazards.

Asphyxiation is the leading cause of death in confined spaces. The asphyxiations that have occurred in permit spaces have generally resulted from oxygen deficiency or from exposure to toxic atmospheres. In addition, there have been cases where employees who were working in water towers and bulk material hoppers slipped or fell into narrow, tapering, discharge pipes and died of asphyxiation due to compression of the torso. Also, employees working in silos have been asphyxiated as the result of engulfment in finely divided particulate matter (such as sawdust) that blocks the breathing passages.

OSHA has, in addition, documented confined space incidents in which victims were burned, ground-up by auger type conveyors, or crushed or battered by rotating or moving parts inside mixers. Failure to deenergize equipment inside the space prior to employee entry was a factor in many of those accidents.

Many employers have not appreciated the degree to which the conditions of permit space work can compound the risks of exposure to atmospheric or other serious hazards. Further, the elements of confinement, limited access, and restricted air flow, can result in hazardous conditions which would not arise in an open workplace. For example, vapors which might otherwise be released into the open air can generate a highly toxic or otherwise harmful atmosphere within a confined space. Unfortunately, in many cases, employees have died because employers improvised or followed "traditional methods" rather than following existing OSHA standards, recognized safe industry practice, or common sense.

The failure to take proper precautions for permit space entry operations has resulted in fatalities, as opposed to injuries, more frequently than would be predicted using the applicable Bureau of Labor Statistics models. OSHA notes that, by their very nature and configuration, many permit spaces contain atmospheres which, unless adequate precautions are taken, are immediately dangerous to life and health (IDLH). For example, many confined spaces are poorly ventilated - a condition that is favorable to the creation of an oxygen deficient atmosphere and to the accumulation of toxic gases.

Furthermore, by definition, a confined space is not designed for continuous employee occupancy; hence little consideration has been given to the preservation of human life within the confined space when employees need to enter it.

It is your obligation as an employer to evaluate your workplace to determine if any spaces are permit-required confined spaces.

You must first determine whether a space is a confined space. If it is a confined space, then you must determine if it is a permit-required confined space. If it is a permit-required confined space, then you must determine whether full permit entry rules apply or less restrictive alternative entry rules apply.

REMINDER: A confined space is characterized by restricted means of entry/exit, size sufficient to contain a worker, and not specifically designed for worker occupancy. A permit-required space is a confined space that has a hazard to health or life associated with it. Hazards may be the result of atmosphere or materials in the space or the result of the shape of the space.

In general, the Permit-Required Confined Spaces Standard requires that you, the employer, evaluate the workplace to determine if any spaces are permit-required confined spaces. If permit spaces are present, and your workers ever are authorized to enter such spaces, you must develop and implement a comprehensive permit spaces program, which is an overall plan/policy for protecting employees from permit space hazards and for regulating employee entry into permit spaces. The OSHA standard includes detailed specification of the elements of an acceptable permit spaces program (29 CFR 1910.146(d)). Permit spaces must be identified by signs, and entry must be controlled and limited to authorized persons. An important element of the requirements is that entry be regulated by a written entry permit system, and that entry permits be recorded and issued for each entry in to a permit space. The standard specifies strict procedures for evaluation and atmospheric testing of a space before and during an entry by workers. The standard requires that entry be monitored by an attendant outside the space and that provisions be made for rescue in the event of an emergency. The standard specifies training requirements and specific duties for authorized entrants, attendants, and supervisors. Rescue service provisions are required, and where feasible rescue must be facilitated by a non-entry retrieval system, such as a harness and cable attached to a mechanical hoist.

The OSHA Permit-Required Confined Spaces Standard provides for alternative (less stringent than full permit procedures) entry procedures in cases where the only hazard in a space is atmospheric and the hazard can be controlled by forced air. The alternative procedure is allowed only in cases where specified requirements for substantiation and notification are met.

Special requirements apply to contractors whose employees work in spaces controlled by others. Employers who engage contractors to work in their permit-required confined spaces also have special obligations pertaining to that arrangement.

If certain kinds of work are done in a permit space, then additional OSHA rules may apply. These kinds of work include telecommunications, electrical (underground), paper/pulp milling, shipbuilding, longshoring and sewer work.

Construction, marine terminal, ship yard employment, and agriculture are not subject to the OSHA General Industry Permit-Required Confined Spaces regulation (29 CFR 1910.146). However, employers in those industries should be aware that their workers are covered when they do work that falls under the general industry category. For example, maintenance, repair, and refurbishing work is covered under general industry rules even though done by "construction" contractors.

You may be able to reclassify a permit-required confined space to non-permit space status if you can permanently eliminate the hazards affecting the space.

The OSHA Confined Spaces Advisor includes an option that will lead you through a series of simple questions to determine if a space is a permit-required confined space and what rule alternatives apply to your situation.