Working zones

Eliminates or controls worker Site work zones and safety standards safety requirements... 

Work zones are often temporary. Many times, onee the work has been eondueted, the zone boundaries ehange and sometimes beeome support zones. Temporary work zones ean be used to eflfeetively manage regulatory seope. Area and personnel exposure monitoring is erueial in order to verify that zoning, eontainments, work praetiees, and proeedures have been designed appropriately and maintain worker health and safety. 

There are three main types of work zones at a hazardous waste site the exelusion (or hot) zone, the eontamination reduetion (or deeontam-ination) zone, and the support (or eold) zone. The following provides a diseussion of eaeh type of zone. 

Worker eomfort areas ean be loeated in site work zones. These eomfort zones allow workers to take breaks and rest without being eontaminated. These areas are designed to maintain the safety of workers and generally require speeial proeedures for ingress and egress, personnel and air monitoring, potable water eonsumption, and restroom use [1],... 

The names, number, and types of zones vary based on the aetivities at the worksite. The important thing to remember is that work zones are established to proteet the workers and the publie. Everyone on the site should understand the hazard(s) and eontrol(s) neeessary to support eaeh identified zone. Wind direetion was mentioned as an important eri-terion in ehoosing the support or elean zone. In most parts of the eountry, wind direetion ean be highly variable. If this is the ease at a given site, how should the support zone be handled The answer may vary based on the eonditions. 

Let s look at another example a small-scale voluntary cleanup that might take place in the lot behind a factory, or a tank being removed at a corner gas station. Although we have the same considerations, these projects are on a smaller scale and will create less of a hazardous condition. The same principles that exist at the large job still should be adhered to on the small job. The work zone should be delineated and controlled to protect workers or the public from entering the work zone. For the small job, caution tape, snow fence, or traffic cones can be used effectively. 

As should be clear now, determining work zones can be a challenge. You can run into unique situations performing hazardous waste... 

Flazardous waste sites are divided into as many or as few zones as necessary to protect worker health and safety. Work zones are established to prevent the spread of hazardous substances from contaminated to clean areas. Radiological work zones should be considered compatible with hazardous waste work zones, differing only in terminology. Diagrams, sketches, and maps should be used as often as necessary and constantly updated and communicated so that workers can be sure that they are appropriately protected [3]. 

Work zones are designed to control access to actual and anticipated hazards. Work zone positioning is based on hazard characterization and exposure assessment. Anticipated work activity, potential releases, and the amount of contaminant dispersion are important for delineating these zones [3]. 

The typical decontamination may include removing any gross contamination in the exclusion zone using equipment that will stay in the EZ (for instance, a hand scraper, a wire brush, etc.). Once gross contamination is removed, the worker (or equipment) might go to the decon pad where washing with a scrub brush, soap, and water might take place. Chapter 10 provides an in-depth discussion of decontamination and work zones. 

The SSAHP for Site A contained procedures and practices that did not reflect actual practices employed by workers onsite. Examples included PPE requirements, decontamination procedures, and work zone identification procedures. 

F. All site control elements of the safety and health program must be fully implemented as described in the program. The purpose of site control requirements is to ensure that only properly trained and authorized individuals enter those areas of the site with potential hazards, and that, in the event of an emergency, rapid assistance can be rendered to employees working in the exclusion zone. This section discusses the findings of two components of site control the establishment and maintenance of site work zones and the establishment and implementation of appropriate confined space procedures. 

One common deficiency in the sites reviewed was the lack of an accurate, up-to-date site work zone map. Of the sites reviewed, only the Site H contractor had established site work zones that were clearly marked on a site zone map. The SSAHP for Site G contained a general discussion of the types of work zones established at the site and the kinds of activities that took place within each zone although the SSAHP... 

Site H was the only site at which the contractor had implemented comprehensive and effective site control elements. The Site H contractor had established site work zones, a buddy system, and site communication procedures consistent with 1910.120(d). This contractor had also established exclusion zones and contamination reduction zones to control migration of site contaminants to clean areas of the site when work within these areas introduced the potential for exposure to hazardous contaminants. The audit team supported this contractor s use of flexible and temporary work zone boundaries based on monitoring results and hazard determinations. 

The bench where decontamination took place was only a few feet from the thermal unit and was not isolated from exclusion zone activities employees moved freely between their work stations in the exclusion zone and the decontamination bench. In addition, the subcontractor did not conduct monitoring activities to support work zone designations. Neither Site K contractor used warning signs to delineate exclusion zones, as required by their respective health and safety plans. 

At the time of the Site I audit, only two established work zones remained on site an exehision zone eneompassing the waste treatment area and a elean zone eneompassing the remainder of the site. Aeeord-ing to the eontraetor s projeet manager, EPA approved this reduetion in site work zones. As a result of this zone designation, workers exit the exehision zone direetly into a elean zone, removing and disearding PPE in a barrel adjaeent to the operations trailer. 

The Site E eontraetor had established fixed work zones based on the potential for exposure but adjusted the barriers to aeeommodate eertain aetivities, sueh as thermal unit maintenanee. Wliile adjusting work zone boundaries aeeording to the potential for eontamination is aeeeptable, worker behavior indieated eonfusion about the zone boundaries and assoeiated work praetiees and PPE requirements. In addition, the audit team observed Site E workers leaving the exelusion zone without performing required deeontamination proeedures. 

All eontraetors at Site J had defieieneies in their work zone praetiees. The eontraetors had established work zones based on the potential for exposure assoeiated with speeifie work tasks. 

Are work zones ineluding Exelusion Zone (EZ), Contamination Reduetion Zone (CRZ), and Support Zones adequately demareated and is restrieted aeeess enforeed [OSHA Referenee. 120(d)(3)]... 

Wlien non-impermeable elothing beeomes wetted with hazardous substanees, is it immediately removed and do you shower Is the elothing disposed of or deeontaminated before it is removed from the work zone [OSHA Referenee. 120(k)(5)(ii)]... 

Rooms with a low standard air temperature in the working zone near the gates (8 °C and below)... 

Air movement is ideal in the working zone, both for thermal comfort and pollution control. 

The demands and design of a local ventilation system (not only local ex hausts) should naturally start with the demanded target levels and the toxicity of the air contaminants (see Chapters 5 and 6). For best performance the exhaust should be close to the source and preferably enclose the source, there should be no disturbances of the flow, and at the same time it should have a low flow rate and be able to minimize the concentration of even quite dangerous air contaminants in the working zone. 

Class HA in a Class IIA BSC, an internal blower (Fig. 10.9,St draws sui-ficient room air into the front grill to maintain a minimum calculated measured average velocity of at least 0.37 m s at the opening of the cabinet. The supply air flows through a HEPA filter and provides particulate-free air to the work surface. Laminar airflow reduces turbulence m the work zone and niim-mizes the potential for cross-contamination. 

The air is then discharged through the rear plenum into the space benvcen the supply and exhaust filters hicated at the top of the cabinet. Due to the relative size of these two filters, approximately 30% of the air passes through the exhaust HEPA filter and 70% recirculates through the supply HEPA filter back into the work zone. Most Class IIA cabinets have dampers to modulate this 30%/70% division of airflow. 

Air curtain A high-velocity air jet that provides an air barrier between two different building or work zones. 

REMEDIATION, DECONTAMINATION, AND SAFETY MANAGEMENT 16.9.1 Site Preparation and Work Zones... 

To reduce the accidental spread of hazardous substances by workers from a contaminated area to a clean area, zones should be delineated on the site where different types of operations will occur, and the flow of personnel among the zones should be controlled. The establishment of work zones will help ensure that personnel are properly protected against the hazards present where they are working, that work activities and contamination are confined to the appropriate areas, and that personnel can be located and evacuated in an emergency. 

This practice went on until recently. Four hundred eighty-one formulations and compounds were included in the official list of pesticides permitted for use in agriculture from 1986-90 [14]. In 1990, the MPC and other health protocols were developed for only 127 pesticides in food products, 105 pesticides in bodies of water used for hygiene and drinking, 78 pesticides in fishery reservoirs, 31 pesticides in farm animal feed, 81 pesticides in the soil, and 119 pesticides in work zone air [1]. There were no MPCs for the remainder of the pesticides permitted for use and, according to existing rules, they should not have been used. Nevertheless, they were. 

Table 2.1. Average data on pesticide content of work zone air and population points in Tajikistan in the 1980s [A86]... 

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