GK Foundry Safety

What to Know About the Silica Standard

By Kay Rowntree
Click here to see this story as it appears in Modern Casting

The revised crystalline silica rule is being challenged in court. The recent Presidential election could change its scope. All requirements don’t have to be met until the middle of 2018.

That doesn’t mean metalcasters should take it easy and put off their preparations.

In March, the Occupational Safety and Health Administration (OSHA) published its long-anticipated respirable crystalline silica rule. Proposed in 2013, the new rule aims to reduce the permissible exposure limit (PEL) to silica in half, from 100 µg (micrograms)/cu.m to 50 µg/cu.m. The rule looks to bring an action level of 25 units over an eight-hour period.

The new rule was set to be effective on June 23, 2016, and all requirements of the rule must be met by June 23, 2018.

Indeed, the rule will challenge the metalcasting industry if it’s enforced as OSHA intended, but there are ways for facilities to comply. Plenty of things must be known in order to be up to the standard.

To start, the PEL and action level are based on an 8-hour time weighted averages. No adjustment is required for shifts longer than 8 hours, and for longer shifts, the worst 8 hours of exposure should be sampled.  The limits are based on the gravimetric measurement of respirable crystalline silica and only respirable sampling methods are to be used.

Facilities must assess the exposures for any employee reasonably expected to be over the action level, via either a performance option or a scheduled monitoring option. With the performance option, there is a burden to make sure employers accurately characterize the exposures if they decide not to sample all employees potentially exposed above the action level. Scheduled monitoring entails initial testing that reflects a worker’s personal breathing zone time weighted averages exposures for each shift and for each job classification in each area.  The tests must be done when work begins. The periodic testing is required to be repeated every six months for jobs with exposures over the action level, and quarterly for jobs with exposures over the PEL. OSHA does not require that every employee be sampled but sampling must be representative of all of the employee’s potentially exposed above the action level.

Any employee who’s affected must be notified within 15 working days of the results and this applies to any exposure assessments and is required whether or not the action level or PEL has been exceeded. If the PEL is exceeded, a description of corrective actions to be taken by the employer is required with the notification.

Compliance Methods
OSHA stresses its position on the hierarchy of controls.  The order of preferred controls is elimination, substitution, engineering controls, administrative controls and personal protection equipment.  When planning to comply with the new standard, it’s important to note respirators are not considered controls. When employees are working in jobs that exceed the PEL, employers must provide respiratory protection until exposures are reduced below the PEL and pursue feasible controls.

The burden to show that a control isn’t feasible is on the employer.

In OSHA’s view, engineering controls are reliable, predictable and provide consistent protection, can be monitored constantly and easily and aren’t susceptible to human error.  Exposure reduction can be achieved via substitution, ventilation, isolation, dust suppression or process changes. The way employees perform tasks can be modified, though that requires training to know how practices create exposure.
If silica containing abrasives are used, the hierarchy of controls also needs to be followed.  Non-silica containing  abrasives should be considered, but even when used, respirable crystalline silica exposures can still occur when sand is removed from castings.

As for simply rotating employees out of areas where there is silica exposure, OSHA didn’t prohibit the practice but doesn’t consider that to be an acceptable alternative to avoid costs. It also doesn’t think pervasive exposures to respirable crystalline silica justify allowing rotation.

Respirators are required and must be used properly when the PEL is exceeded. They are allowed to be used in four circumstances:  until controls are installed and implemented and successfully reduce exposures below the PEL,  when controls are not feasible, when controls cannot sufficiently reduce exposures below the PEL and when employees enter regulated areas. OSHA thinks respirators are less reliable than engineering and work-practice controls and do not provide a level of protection the equivalent of engineering controls.

Regulated Areas
A regulated area is an area where an employee’s exposure to airborne respirable crystalline silica exceeds, or can reasonably be expected to exceed, the PEL.  Designating these areas helps raise awareness and reduce the number of employees exposed over  the PEL. Just because a particular employee’s exposure assessment results indicate the employee’s exposure is above the PEL, does not mean every area the employee visited on the day he or she was sampled exceeds, or can reasonably be expected to exceed, the PEL. Establishing the boundaries of the Regulated Area will be challenging when employees move around.

Companies are required to demarcate the area, post a sign with specific wording at entrances to the area, and limit access to these areas. Everyone entering the regulated area must wear a respirator.

OSHA concluded wet methods and HEPA-filtered vacuums are highly effective. It also believes compressed air, dry sweeping and dry brushing contribute to employee exposures, and there’s evidence wet method and HEPA vacuuming might not work in all situations. The standard allows dry sweeping and brushing in limited circumstances where wet methods and the use of HEPA vacuums are not feasible. Compressed air can be used for cleaning where it is used in conjunction with ventilation to collect the dust.

It is important to note the ‘‘unless’’ clause indicates the employer bears the burden of showing a cleaning method is not feasible in a particular situation, and OSHA expects the vast majority of operations will use HEPA vacuuming or wet methods that minimize the likelihood of airborne dust exposure. Similarly, where compressed air is used to clean clothing and surfaces without a ventilation system designed to capture the dust cloud created, the employer must be able to demonstrate no alternative cleaning method is feasible.

Written Exposure Control Plans
These plans are performance based and meant to establish and implement what a facility intends to do to control airborne respirable crystalline silica exposure. The plans must be prepared even if there are no exposures exceed the action level or PEL.  Plans must include a description/identification of all tasks with respirable crystalline silica exposure, a description of controls and protective measures (engineering, work practice and respiratory protection) used for each identified task, and a description of housekeeping measures used to limit exposure.
These must be annually reviewed and updated, and metalcasters need to make their plan readily available to employees and their representatives and OSHA.

Medical Surveillance
Medical surveillance will eventually apply to all employees working in jobs over the action level for more than 30 days per year.  The purpose of these programs is to identify silica related problems at early stages so intervention can be done, determine if employees can continue to be exposed to silica and determine an employee’s fitness to wear a respirator.

Examinations must be offered at no cost and at a convenient time and place to the employee.

The exams will look into medical and work history and include a physical exam. Chest X-rays, pulmonary function tests, a tuberculosis test (only at the initial exam) and any other tests deemed necessary by a healthcare professional will be taken. These exams must be completed within 30 days of initial assignment to a job with exposures over the action level or PEL, and at least every three years but even more frequently if a healthcare professional recommends this. 

Hazard Communication
Information about the health hazards of respirable crystalline silica should already be provided through your company’s hazard communication program but the respirable crystalline silica standard has some additional requirements.  

Training must include information about silica’s specific health effects. Signs must be posted at entrances to regulated areas.  Employees exposed over the AL must demonstrate that they understand the hazards, the tasks where exposure occurs, measures to be taken to protect themselves, the provisions of the OSHA Standard, and the purposes and description of the medical surveillance program. Facilities must make a copy of the OSHA Respirable Crystalline Silica standard available to employees.  

This article was adapted from a presentation given in November at an AFS silica compliance conference. Future seminars will be held January 9-10 in Arlington, Texas, and April 27-28 in Milwaukee. Go to www.afsinc.org for more information.

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