Fixed and portable types of breathing apparatus are used. In brief, they contain an oxygen cylinder that is connected via a regulator to the mask. Personnel use them when working in an area that has a possibility of toxic gas release.
Portable breathing apparatus contain the following items:
In many movies (especially war movies) film actors and actresses have been shown wearing a breathing mask. Therefore breathing air apparatus (BA) is a fairly familiar instrument and a photo is not shown.
Access to each reservoir compartment is needed for personnel, plant and materials. Access openings are usually sized to allow entry by a person wearing breathing apparatus. Access openings for plant and materials should be larger. Upstands should be provided around each opening to prevent surface water entering the reservoir. Covers to all openings must be robust but they do not normally need to be designed to support heavy loadings. They must be secure to prevent unauthorized access and must not allow rainwater to enter the reservoir. Lift-off covers risk introduction of mud and debris into the reservoir; therefore hinged covers are preferred but they must have an effective system for holding them in the open position when the access is in use.
For personnel entry into the reservoir the preferred arrangement is an inclined ladder leading to a platform about 2.5 m below the roof and a stairway leading from the platform to the floor. Where a stairway height exceeds 3 m, an intermediate landing is required. Reinforced concrete construction is recommended for platforms and stairways as this needs less long-term maintenance. The platforms can either be supported on columns or, in some cases, cantilevered from the walls. Alternatively the platforms and stairways can be fabricated in galvanized steel or anodized aluminium alloy. The same material should be used for the ladder. Typically two separate human accesses should be provided into each compartment, near opposite corners to assist ventilation of the compartment when work is in progress and to provide an escape route in an emergency.
Access for plant and materials has to be unobstructed to allow items to be lowered vertically to the compartment floor. The clear opening needed for small plant and materials for normal maintenance should be not less than 1.5 m×1.0 m to allow a wheelbarrow to be lowered. Consideration should be given to the provision of removable handrailing around such openings, or of sockets into which it could be fitted. For reservoir compartments exceeding about 10 000 m3 a second and larger access for plant and materials should be considered if larger mechanical equipment might be needed for cleaning or major repairs. It is important to ensure that unauthorized vehicles cannot reach the roof or be used outside any specially strengthened areas of the roof.
Exposure and Exposure Monitoring
Inhalation is the major route of human exposure to gaseous methyl bromide. Workers handling liquid methyl bromide can also have dermal contact either directly or through accidental spills or contaminated clothing. Personal protective equipment, including self-contained breathing apparatus, may be required to minimize the exposure. Buffer zones that increase the distance between treatment sites and residential locations reduce the exposures of those who are nearby. Methyl bromide air concentration is measured by air sampling or estimated from air dispersion models.
Consumers of fumigated postharvest commodities may be exposed to methyl bromide and inorganic bromide. Maximum residue levels (MRLs, or ‘Tolerances’ in the United States) of inorganic bromide are established for more than 90 commodities. These are the highest concentrations allowable in or on the commodities. No MRLs or tolerances are established for methyl bromide, which has been detected in some treated commodities (e.g., nuts). At a given exposure concentration, children generally have higher overall body burden from all routes due to their higher intake (inhalation volume, amount of food intake) or contact on a per body weight basis.
In case of explosion, the substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Containers may explode when heated. Runoff material may pollute waterways. Individuals involved in production should wear positive pressure self-contained breathing apparatus in addition to chemical protective clothing that is specifically recommended by the manufacturer, although it may provide little or no thermal protection. Structural firefighters’ protective clothing provides limited protection in fire outbreak circumstances only; it is not effective in spill situations where direct contact with the substance is possible. Containers must be removed from fire area and fire control water must dike for later disposal; water spray or fog should be used instead of straight streams. Firefighting must be performed from the maximum distance possible, and/or use unmanned hose holders or monitor nozzles. Water inside containers must be avoided. Distance should be maintained from tanks engulfed in fire. Individuals in charge of vessels or facilities are required to notify the National Response Center immediately when there is a release of this designated hazardous substance in an amount equal to or greater than its reportable quantity of 10 lb or 4.54 kg. Section 8(a) of the US Toxic Substances Control Act requires manufacturers of this chemical substance to report preliminary assessment information concerned with production, use, and exposure to these compounds.
If there is an exposure to CX, moving immediately upward and toward an area where fresh air is available is an important protection since CX is heavier than air and settles down (Patocka and Kamil, 2011). Pressure-demand, self-contained breathing apparatus (SCBA) could be helpful in situations of CX exposure. Although CX can attack butyl rubber gloves and boots, these are protective against field concentrations of CX. Since CX is absorbed very rapidly, skin and eye decontamination are needed immediately; hence, the timing of decontamination is very critical. CX reacts with tissues very rapidly and causes extreme pain and itching—if this occurs then decontamination will have no effect. All alkaline agents can be used for chemical inactivation. Chlorinated agents cannot be used for CX decontamination and water can only be used to flush the chemical from eyes. Clothing exposed to CX should be immediately removed and sealed in a bag to avoid any further exposure and contamination. Immediate and lifesaving care might be required within minutes following CX exposure at an emergency station. Long-term care, hospitalization, and lifesaving surgery can be required, and delay in this care can adversely affect the injury and survival outcomes.
There is no effective antidote available against CX-induced toxicity and any treatment is mostly helpful to reduce indications, prevent infections, and help healing. Systemic analgesics are a better option compared with topical anesthetics because use of the latter may increase the severity of corneal damage (Ubels et al., 1982). Dilution with water or milk could be helpful in oral exposures. For eye injury, washing with a large amount of water could be supportive, while for necrotic skin lesions, surgical intervention may be essential. Recovery depends on the extent of injury and could take several months (Patocka and Kamil, 2011). Reports indicate that mast cell activation and histamine release could be involved in CX-induced inflammation, toxicity, and urticaria Employment of therapies that can ameliorate anaphylactic symptoms and counteract mast cell activation-related release of inflammatory mediators like histamine alone or in combination is a pioneering strategy for investigation to ameliorate CX-induced morbidity and mortality from its cutaneous exposure. Additionally, second-generation antihistamine with mast cell-stabilizing properties, analgesics, and antibiotics could be given to reduce pain, prevent infections, and promote healing.