Requirement to Monitor for Hydrogen Peroxide
One of the topics that we often receive questions on concerns whether there is a legal requirement to monitor for hydrogen peroxide. The short answer is that there is no regulation from OSHA explicitly saying that hydrogen peroxide must be monitored, just as there is no explicit order requirement to monitor for carbon monoxide in a steel mill or hydrogen sulfide in a petroleum plant.
The reason why there is no statement requiring monitoring, is because OSHA along with most other government agencies intentionally write their regulations to set goals not prescribe means to create a safe workplace. i.e. performance based versus prescription based regulation. the goal is a safe work environment, gas detection is a means to achieving it. There are two reasons for this performance based approach. The first is that developing regulations is a slow process and if OSHA were to specify a particular method, it would probably be obsolete even before the final rule was published in the Federal Register. The second reason is that the circumstances at every employer is different and so the means to solve an exposure problem at one facility may be inapplicable to another facility. For example, the same regulations governing workplace exposure to hydrogen peroxide apply to a hospital sterilizing medical equipment, a titanium plant using hydrogen peroxide to pickle titanium ingots to remove mill scale and a sewage treatment plant using hydrogen peroxide to reduce odor emissions.
The Occupational Safety and Health Act (1970), imposes a legal duty on employers to “furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees.”
[Sec. 5] The hazards of exposure to hydrogen peroxide vapor are well known and have been for decades, and OSHA sets the legal standard for when exposures to hydrogen peroxide are considered free from recognized hazards etc. in its Permissible Exposure Limits (PELs) “An employee’s exposure to any substance in Table Z-1, the exposure limit of which is not preceded by a “C”, shall not exceed the 8-hour Time Weighted Average given for that substance any 8-hour work shift of a 40-hour work week.” The permissible exposure limit for hydrogen peroxide is 1 ppm calculated as an 8 hr time weighted average and the employer has an affirmative legal duty to ensure that the PEL is not exceeded.
Many people believe that hydrogen peroxide is completely safe, after all it is sold in super markets for treatment of minor cuts. However, gas or vapor sterilization is achieved by exposing the articles to be sterilized to high enough concentrations of reactive gases or vapors to ensure that all microbial life is destroyed. Some people may have received assurances from the folks who sold them a hydrogen peroxide sterilizer that their equipment could never leak. People in sales are often very enthusiastic about their products and often portray them in their best light. Modern sterilizers available today are indeed designed and manufactured to the highest engineering standards, and most are tested for leaks as part of the design process. However, as with any complex piece of equipment components can fail, user error happens and, of course wear, and tear takes its toll. Even though the sterilizers contain many safety features and are designed not to leak, the manufacturers will usually acknowledge that leaks can sometimes occur. If you are assured that it cannot leak, just request a statement to that effect in writing.
ChemDAQ has many customers with monitors monitoring their hydrogen peroxide sterilizers. In case further evidence were needed that sterilizers can sometimes leak, last year, one of our hospital customers installed ChemDAQ’s gas monitoring system for their four new hydrogen peroxide sterilizers (no names here!). All four sterilizers emitted a cloud of around 20 to 40 ppm hydrogen peroxide each time the door was opened at the completion of the cycle, which would have been particularly harmful if people are reaching in to retrieve the load, especially since the NIOSH immediately dangerous to life and health level for hydrogen peroxide is only 75 ppm. The FDA’s MAUDE data base also provides other examples of sterilizer malfunction including exposure of workers to hydrogen peroxide vapor.
Employers must ensure that their employees are not exposed to hydrogen peroxide levels greater than the PEL, but hydrogen peroxide has almost no odor, so odor cannot be used to detect the presence of a hydrogen peroxide leak. Therefore, absent some kind of monitor, it would be very difficult to measure the hydrogen peroxide concentration.
Some facilities use badges for hydrogen peroxide, but badges suffer from two major defects. A typical badge is worn for a shift and then sent to a lab to be analyzed (results are typically returned in 1 – 2 weeks). Thus badges provide no warning of current exposure; they merely document exposures that have already happened. The second drawback is that leaks, like other faults usually occur at unexpected times and so if, for example badgering, is performed every month, then there will be between one to 31 days (plus badge analysis time) before any leak is discovered.
A continuous monitor offers greatly superior performance by providing the instantaneous hydrogen peroxide concentration, and alarms if the concentration goes too high thus providing real-time protection of employees. Most systems also include the capability to log data, calculate time weighted average exposures and warn if the OSHA PEL will be/has been exceeded and provide record keeping, reports etc. that enable an employer to demonstrate that their employees have not been exposed above the OSHA PEL.
In summary, installing a gas monitor for hydrogen peroxide is NOT mandated by OSHA, but OSHA does require that employers ensure that employees are not exposed to hydrogen peroxide over the PEL. Hydrogen is odorless and generally imperceptible until present at concentrations greater than the PEL and so some kind of analysis method is required to detect it. While the employer is free to employ any effective method to ensure that its employees are not overly exposed to hydrogen peroxide, continuous monitoring is the most effective method for employers to meet the OSHA requirement. Since hydrogen peroxide vapor is imperceptible until above safe levels, if there is a leak, how will you know if you are safe?