Priority Existing Chemical Assessment Reports -

'Savinase' - a proteolytic enzyme

 

Introduction

The chemical known as 'Savinase', a proteolytic enzyme, was declared by the Minister for Industrial Relations as a Priority Existing Chemical (PEC), under section 55 of the Act, by notice in the Chemical Gazette of June 2, 1992. The declaration was limited to the use of proteolytic enzymes in the detergent industry.

In summary, the grounds for declaration were:

• Past exposure of Australian workers to proteolytic enzymes in detergents had resulted in asthma-like reactions. Proteolytic enzymes are known respiratory sensitisers in humans.

• If detergents containing proteolytic enzymes are to be manufactured in Australia, potentially a significant number of workers could be exposed to this hazard.

There was substantial agreement by industry and employee organisations on the need for an objective scientific assessment of proteolytic enzymes in the detergent industry.

With this in mind the objectives of the assessment were to:

• characterise the potential health hazards presented by proteolytic enzymes; and

• to determine if these hazards could be satisfactorily controlled in the workplace.

In beginning to assess this chemical as a priority existing chemical it was recognised that 'Savinase' was only one of the commercial names for this class of enzyme, and proteolytic enzymes used in the detergent industry fall into a general category of enzymes known as 'proteinases'. A range of Chemical Abstract Services numbers (CAS Numbers) have been assigned for proteinases and there are a multitude of common names, commercial or trade names, to be found. Proteolytic enzymes are more commonly referred to as proteinases in the nomenclature considered.

Because of this confusing nomenclature it was found to be inappropriate to limit this assessment just to Savinase, and therefore other proteinases used in the detergent industry have been considered. Accordingly, the generic name 'proteinase' is used in this report.

This report focuses on the use of proteinases in the manufacture of enzymatic detergents, not on the manufacture of proteinases themselves, and is further focussed on use in laundry detergents.

Background

A variety of enzyme products have been developed for use in so-called 'biological or enzymatic detergents' to enhance the removal of organic material from textile fibres. The most widely used of these are proteinases whose function and mode of action is to remove protein stains, such as grass, blood, egg and human sweat, by proteolytic degradation to more soluble polypeptides and amino acids.

Following the introduction of enzymatic detergents in the late 1960s, it soon became apparent that occupational exposure to enzyme dusts could cause skin irritation and allergic respiratory reactions. Respiratory sensitisation, also known as enzyme or occupational asthma, was recognised as a common occurrence in detergent workers worldwide,  including Australia. Adverse health effects were particularly prevalent in workers in the detergent industry exposed to high enzyme dust levels. Adverse effects appeared to be reversible in most workers following removal from further exposure to enzyme-containing dust. Of the many studies of workers in the detergent industry, only one report has suggested that there may be a longer term loss of respiratory function in some individuals.

In Australia, enzyme-elicited allergic respiratory reactions in workers using enzyme powders led to an ACTU ban in 1971 on the manufacture of enzymatic detergents. This action was accompanied by a voluntary withdrawal from the use of enzymes in detergent products by the main Australian detergent producers. The ACTU ban on the use of proteolytic enzymes in the soap/detergent industry still stands in 1992.

Detergents containing enzymes, or 'enzymatic detergents', have continued to be manufactured and used in Europe, America and many Asian countries. Recognition that enzyme asthma in workers in detergent factories was due to exposure to high levels of enzyme dust led to major changes to work practices in the 1970s to reduce airborne respirable dust levels. Engineering controls were introduced to achieve stricter dust control. Guidelines for the safe handling of enzyme-containing detergents, such as the United Kingdom Soap and Detergent Industry Association (SDIA) Operating Guidelines, were developed and implemented by the detergent industry. Enzymes were encapsulated to prevent the release of fine dust particles during their manufacture and use. To monitor the effectiveness of the workplace changes, dust monitoring and health surveillance of workers were introduced in detergent factories.

Largely as a result of these changes since the early 1970s, there has been a marked reduction in the levels of airborne enzymes in detergent factories and in the incidence of acute respiratory illness in detergent workers. In the past decade there have been only a few reports in the literature of sensitisation in workers handling encapsulated enzymes.

During 1992 a number of companies began to import laundry detergents containing proteinases into Australia. A reassessment of the use of proteinases in laundry detergents in Australia, including possibilities for domestic detergent manufacture, is therefore timely. It is generally agreed that enzymatic detergents should only be manufactured here if the risk of adverse health effects to workers is acceptably low.

Applicants

• Ajax Chemicals, 291-303 Woodpark Road, Smithfield, NSW 2164;

• Amway of Australia Pty Ltd, 46 Carrington Street, Castle Hill, NSW 2154;

• Campbell Brothers Ltd, Campbell Street, Bowen Hills, QLD 4006;

• Colgate-Palmolive Pty Ltd, Level 15, 345 George Street, Sydney, NSW 2000;

• Cussons Pty Ltd, 282-300 Hammond Road, Dandenong, VIC 3175;

• Harcros Industrial Chemicals, 3-5 Alan Street, Rydalmere, NSW 2116;

• Kao (Australia) Marketing Pty Ltd, Suite 403, 32 Walker Street, North Sydney, NSW 2060;

• L&K:Rexona Pty Ltd, Pembroke Road, Minto, NSW 2566;

• Novo Nordisk Bioindustrial Pty Ltd, 22 Loyalty Road, North Rocks, NSW 2151; and

• Solvay Biosciences Pty Ltd, 530 Springvale Road, Glen Waverley, VIC 3150

Chemical identity

Proteolytic enzymes, such as Savinase, are classed as proteinases, but due to the fact that they are derived from bacterial strains, they have a number of different identifying names and Chemical Abstracts Services (CAS) numbers, including proteinase (CAS no. 9001-92-7), subtilisin (9014-01-1), Bacillus alkaline proteinase (9073-77-2) and (Myxobacter alpha-lytic) proteinase (12585-31-8). Savinase is the trade name for one proteinase product of Novo Nordisk A/S, Denmark.

Other names for proteinases include alkaline bacterial proteolytic enzyme, alkaline protease, bacillus alkaline proteinase, microbial serine proteinase, protease, proteolytic enzyme, serine proteinase, serine protease, serine proteolytic enzyme, and subtilisin protease.

Trade names for proteinases include Alcalase, Durazym, Esperase, Kazusase, Maxatase, Opticlean, Optimase and Savinase.

It is generally regarded that the properties and health effects of all proteinases are similar.

Use

The principal use of proteolytic enzymes is in the laundry detergent industry. At present, proteinases are imported as ingredients in commercial laundry detergents and in small quantities for incorporation into detergents. Depending on the market acceptance of laundry products containing proteinases in Australia, import of proteinases could increase from 5 tonnes in the first year to 50 tonnes per year.

To manufacture these detergents in Australia, proteinases will be imported as enzyme granulate for inclusion in detergent powders and liquid or slurry preparations for inclusion in liquid detergents. Enzyme granules contain between 1% and 5% enzyme protein embedded in a core of inorganic salts, with encapsulation in an inert protective coating. Enzyme liquid and slurry preparations contain between 2% and 5% enzyme protein and are usually formulated in polyols, glycols and water, or ethoxylated alcohols.

Proteinases will be included in laundry detergents at a maximum concentration of 0.05% by weight.

A spray liquid laundry stain remover, which contains proteinases at a concentration of 0.007%, is also available to the public.

Physical and Chemical Properties

Detergent proteinases are derived from the fermentation processes of non-pathogenic, alkalophilic strains of bacteria and, in particular, the Bacillus genus, such as Bacillus subtilis, Bacillus lentus and Bacillus licheniformis. These enzymes are particularly stable under the conditions of temperature and alkalinity found in laundering and are more specifically referred to as 'alkaline' or 'high alkaline' proteinases.

Proteinases have a molecular weight range of 22,000 to 28,500. Proteinases are readily soluble in water, stable at room temperature, and have a low vapour pressure. They show optimum activity at pH 8 to 11, and at 40ûC to 60ûC. The enzymes are inactivated at pH less than 4, and at temperatures above 80ûC.

Human Health Effects

When proteinases were first used in the manufacture of enzymatic detergents in the 1960s, proteinase dusts caused allergic respiratory reactions, such as asthma, and skin irritation in workers.

Respiratory sensitisation is noted as an increased responsiveness of the respiratory system upon inhalation of a respiratory sensitiser. Once this increased responsiveness has developed, any further exposure to the respiratory sensitisers, even at much lower levels, may cause symptoms. Sensitisation is indicated by positive reactions in immunological tests, such as skin prick testing and ELISA or RAST blood tests. Individuals found by immunological tests as being sensitised will not necessarily develop respiratory symptoms on exposure.

Respiratory symptoms were particularly prevalent in detergent workers exposed to very high levels of enzymes fine powders. The symptoms included sneezing, nasal congestion and increased nasal secretions, sore throat, tightness in the throat or chest, wheezing and shortness of breath. Severity of symptoms usually related to the degree of exposure and generally lasted for a few hours to several days, although certain clinical effects have been reported to persist much longer.

Earlier studies indicated that sensitisation, a positive immunological response, was more common amongst those persons who were more susceptible to allergic reactions ie atopic individuals. These studies also demonstrated that the majority of sensitised individuals do not develop respiratory symptoms. Many studies have shown that non-atopics can also become sensitised to proteinases.

Exposure to proteinase dusts also resulted in skin irritation in workers at high enzyme concentrations, after prolonged contact, in moist conditions, and when abrasion was present.

There is no evidence that proteinases cause skin sensitisation in humans.

Reports have shown a decline in the percentage of overseas workers in the detergent industry becoming immunologically sensitised and the near elimination of workers developing respiratory symptoms. This has been largely due to the reduction of enzyme dust levels and control of worker exposure. The reduction of enzyme dust levels has been achieved by encapsulation, improved engineering controls and safer work practices.

Assessment of Animal Toxicological Data

In animals, proteinases have a low acute oral toxicity but a high acute inhalational toxicity in rats, and cause slight skin irritation and moderate eye irritation in rabbits. No skin sensitisation was noted in guinea pigs exposed to an enzyme liquid, but skin sensitisation was noted in guinea pigs exposed to crushed granules containing proteinase. The evidence for skin sensitisation in animals is therefore equivocal. Two 28-day repeated-dose gavage studies in rats using two different enzymatic powder detergents showed no specific target organ toxicity. In genotoxicity studies, proteinases tested negative in in vitro bacterial mutation assays and in in vivo mammalian tests. Respiratory sensitisation by proteinases has been documented in guinea pigs and monkeys.

Animal data shows that the toxicological effects of proteinase exposure in animals is similar to the effects seen in humans.

Assessment of Occupational Exposure and Health and Safety Effects

Experience has shown that exposure of humans to proteinases can cause respiratory sensitisation. To a lesser extent, proteinases can cause skin irritation, particularly at high concentrations and under prolonged contact.

The most likely routes of worker exposure to proteinases are inhalational and dermal. Hence, any activity that leads to dust or aerosol formation will increase the potential for worker exposure.

During the manufacture of enzymatic detergents, worker exposure is most likely to occur when handling the enzyme preparations (granulates, liquids or slurries), during maintenance, when reclaiming enzymatic detergent powder and liquid, and when cleaning up spills.

Proteinases will be imported in granulate, liquid and slurry forms. The mean particle size of the granules is 500-700 micro.m, well above the inspirable size of 185 micro.m, and the liquid and slurry forms have low volatility, so the risk of worker exposure by inhalation is reduced. However, inhalational exposure to any level of enzyme presents a risk of respiratory sensitisation occurring. As proteinases are potent sensitisers, worker exposure to proteinases must be minimised.

Exposure to low levels of enzyme is unlikely to cause skin irritation and there is no evidence that skin sensitisation occurs in humans.

Encapsulation of the enzyme is an important step in the control of enzyme dust levels. Intact granules are not inspirable and granulate in the "as supplied" condition contains very low amounts of respirable enzyme. However, an independent assessment has shown that when the granules are subjected to harsh conditions the friable core is exposed. Care must be therefore be taken to ensure the integrity of the granules. Normal handling and storage conditions should not cause such damage to the granules.

Air monitoring data from overseas has shown that enzyme dust levels can be maintained at very low levels, and usually well below the exposure standard of 0.06 micro.g/m³.

Exposure to proteinases can be controlled at very low levels by good quality encapsulation of the enzymes, engineering controls (such as enclosure and ventilation), safe work practices and the use of protective clothing and equipment where appropriate. For example, in the United Kingdom the SDIA Operating Guidelines provide detailed information on the measures necessary to control exposure and have been adopted by many detergent manufacturers. Data provided shows that adoption of these guidelines has successfully controlled the atmospheric levels of proteinases and therefore worker exposure in the UK detergent factories.

Industry best practice can also reduce the level of worker exposure, for example, fewer spills and less product reclaiming due to packaging problems.

Overseas experience has shown that the effective control of worker exposure to proteinases has resulted in the near elimination of clinical symptoms in workers.

Although the toxicities of other enzymes used in laundry detergents have not been assessed in this report, the control measures outlined in this report should also be appropriate for controlling exposure to these enzymes.

Public Health Assessment

Proteinases will be included in domestic laundry detergents, powders and liquids, at a maximum concentration of 0.05% by weight. Depending on the acceptability of laundry products containing proteinases, public exposure to the proteinases may be widespread but only at very low levels.

Accidental spillage during transport of the imported enzymes or spillage of damaged detergent packages would add little to public exposure. The enzyme is biodegradable and discharge of enzyme containing detergents in effluents to the municipal water is unlikely to present adverse effects to human health.

There have been a limited number of published papers on the public health aspects of enzyme-containing laundry detergents. The incidence of primary irritation among users is unlikely to be increased by enzymes in detergents due to the low concentration of enzymes. Two studies indicate that exposure of consumers, including infants, to fabrics washed in the enzyme containing detergents or presoak agents did not increase the risk of primary skin irritation. Studies have shown that enzymatic detergents do not appear to increase the potential for skin sensitisation or respiratory sensitisation in consumers, including atopic individuals.

Recently, an air propelled aerosol (spray) stain remover containing proteinase was introduced to the Australian domestic market. The product, NEON, is water based and contains 0.007% proteinase. Data provided on the product show that the smallest droplet size is 13.4 µm and therefore the spray has no respirable fraction. Company laboratory tests indicate that when NEON is sprayed on to a fabric from a distance of 150 mm, 98.5% of the expelled product is deposited on the fabric. Therefore, due to its manner of use and large droplet size, the spray is unlikely to be inhaled under normal conditions of use. However, any spray presents a potential inhalational hazard if misused. As proteinases are respiratory sensitisers, it is recommended that an appropriate warning, such as "Caution: avoid breathing spray", should be included on the label of spray laundry products containing proteinases to ensure that the spray is not inhaled.

Therefore, due to low level of exposure under normal use conditions, proteinases in laundry products are unlikely to pose a significant health and safety hazard to the public.

Environmental Assessment

As proteinases are intended for use in detergent products, they will ultimately be released to the aquatic environment via discharge of used washing solution to the sewerage system. The predicted environmental concentration of 0.05 ppm in sewage water would be swiftly reduced to insignificant levels by biodegradation in sewerage treatment plants and dilution in the receiving waters.

Formulation wastes at the manufacturing sites in Sydney, Melbourne and Brisbane will amount to approximately 30 g proteinase per day at each site, with ultimate release of denatured protein to the effluent at less than 1 ppm.

Tests indicate that proteinases are readily biodegradable. Proteinases are not expected to bioaccumulate or to exhibit ecotoxic characteristics because they have a high molecular weight, high biodegradation potential and high water solubility. An acute aquatic toxicity study indicates that Savinase is practically non-toxic to fish. The likely environmental concentrations of proteinases are at least 3 orders of magnitude lower than acute aquatic toxicity levels.

Proteinases are unlikely to present a hazard to the environment at any stage of their use.

Conclusion

From the assessment of the hazard of proteinases, overseas experience, United Kingdom SDIA guidelines, air monitoring data and health surveillance data, we have concluded that proteinases can be used safely in Australia if the appropriate control measures are implemented and adhered to.

Recommendations

Proteolytic enzymes used in the detergent industry, such as Savinase, fall into the generic category known as proteinases. Proteinases are the fermentation product of a number of differing bacterial strains and these products have been given different common and trade names. However, the properties and health effects of proteinases are similar. This assessment report has considered proteinases used in laundry detergents.

Proteinases, which include Savinase, are proven human respiratory sensitisers and are classified as hazardous substances against the National Occupational Health and Safety Commission's Guidance Note for Determining and Classifying a Hazardous Substance. As proteinases are hazardous substances, employers should be aware of their obligations to provide information, eg MSDS and Labels, about the hazards of proteinases and to assess and control the risks to health. Further details of these obligations, consistent with employers general duty of care, are provided in the National Commission's Control of Workplace Hazardous Substances: National Model Regulations and National Code of Practice.

As all States and Territories have made a commitment to enact uniform regulations consistent with the national model regulations in 1993, employers should read the recommendations of this report in conjunction with the obligations set out in the regulations.

As a sensitiser it is not possible to identify a minimum concentration at which exposure to proteinases does not cause sensitisation, ie an immunological response. There is evidence that once a person has become sensitised they are more likely to develop symptoms at concentrations far below levels typically seen as hazardous. However, experience has shown that in well controlled environments adverse health effects such as respiratory symptoms are unlikely to develop in sensitised individuals. Exposure to proteinases must be minimised.

Safe Use

The availability of operating guidelines developed overseas, for example by the United Kingdom Soap and Detergent Industry Association, and work being completed in Australia by the NSW Workcover Authority, such as the Code of Practice for Safe Handling and Storage of Enzymatic Detergent Powders and Liquids, together with the findings and recommendations of this assessment report provide an sound basis by which proteinases can be used safely by the Australian detergent industry.

Code of Practice

It is recognised that there is a need for a Code of Practice which addresses the use of proteinases in detergent manufacturing processes in Australia. It is recommended therefore that consideration be given by the National Occupational Health and Safety Commission (ASCC) to develop a Code of Practice for proteinases to give specific guidance to employers in this area. Because difficulties in providing control for proteinases are shared with other sensitisers the need for a generic Code of Practice for sensitisers which would encompass proteinases as well as other occupational sensitisers, such as isocyanates, is further recommended.

Exposure Standard

It is recommended that ASCC give consideration to reviewing the peak limitation exposure standard and replacing the peak value with a time weighted average value. Such a revision would facilitate compliance with the exposure standard.

It is also recommended that ASCC review the current exposure standard of 0.06 µg/m3, with a view to reducing the standard based on considerations such as achievable levels of atmospheric proteinases and levels at which sensitisation has occurred.

Health Surveillance

Workers involved in the manufacture of enzyme-containing detergents should undergo health surveillance.

A pre-placement medical check should be carried out and used as a base line to assist in identifying future signs of occupational asthma. Atopics should be informed of their increased risk of becoming sensitised and what the implications are. The data does not support a blanket exclusion of atopics from working with enzyme-containing materials.

Workers who experience any asthma-like symptoms, skin or eye irritation after exposure to the enzyme should inform their employer and consult a doctor.

It is recommended that ASCC give consideration to including proteinases in the schedule of substances requiring health surveillance required under the National Commission's Model Regulations to Control Workplace Hazardous Substances. While this report has identified some generic requirements for health surveillance detailed consideration needs to be given to defining a specific health surveillance program. Development of guidelines for occupational physicians which include a clear statement of the importance of early diagnoses, a definition of occupational asthma, and management of such cases and appropriate use of the specified health surveillance program is also recommended.

Spray Laundry Products

Proteinases are sold to the public in spray laundry products. It is recommended that an appropriate warning, such as "Caution: avoid breathing spray", should be included on the label of spray laundry products containing proteinases to ensure that the spray is not inhaled.

It is also recommended that the droplet size of spray laundry products containing proteinases should not be in the respirable range, that is less than 7 micro.m.

Control of Occupational Exposure

To minimise worker exposure to proteinases, detergent manufacturers should aim to control atmospheric proteinases at the lowest practicable level. The level should not exceed the current exposure standard. Overseas experience has shown that levels can be maintained well below this standard.

To minimise and monitor worker exposure to proteinases the following guidelines and precautions should be observed.

Encapsulation

Good quality encapsulate and careful handling of the granulates are necessary in order to avoid the generation and dispersion of enzyme dust.

Detergent manufacturers should obtain a copy of the elutriation test results for each batch of enzymes to ensure that they are using good quality encapsulated material.

Batches of enzyme should be randomly checked by the detergent manufacturer using the elutriation test to ascertain whether damage to the encapsulate is occurring during transportation.

Engineering Controls

The detergent manufacturing process should be as automated as possible.

In the liquid detergent plant gravity feed should be used where possible to reduce pressure in the system.

Enclosure

• The enzyme feed area should be enclosed.

• The reclaim area should be enclosed.

• Enzyme handling equipment, which includes conveyors, storage tanks and mixing tanks should be enclosed.

• The filling machine should be enclosed.

• Any pump and pipe flanges carrying enzymatic detergents should be encased.

• In the liquid detergent plant gravity feed should be used where possible to reduce pressure in the process.

Ventilation

• Ventilation should ensure that the level of airborne enzyme does not exceed the exposure standard, which is currently 0.06 micro.g/m³.

• General ventilation of the plant is recommended.

• For powder and liquid processes the enzyme feed room and powder reclaim room should also be under general ventilation.

• Local ventilation is required at specific points of the process.

For the powder process:

• enclosed conveyors carrying the enzyme and the dosed product, the filling machine, and the operation for powder reclaim should be under a local exhaust system connected to an efficient dust collecting unit; and

• detergent powder dust should not be exhausted to a wet scrubber as excessive foaming may occur and this reduces the efficiency of the unit.

• the liquid process:

• all storage and mixing tanks, and filling machines should be under a local exhaust system connected to an efficient coalescing filter.

• All ventilation equipment should be regularly checked and maintained.

Safe Practices

• When working with enzymes or enzyme-containing detergents workers should avoid the generation of dust clouds and aerosols.

• Industry best practice should be introduced or maintained to reduce the level of worker exposure. For example, fewer spills and improved practices to reduce product reclaim will reduce the number of workers who would need to carry out these higher risk operations.

• The dosing of enzymes should occur after the major detergent ingredients have been mixed, as late in the process as possible and with minimal mixing.

• Enzyme preparations, ie granulate, liquid and slurry, should be stored in a designated area.

• Good personal hygiene practices should be implemented.

• Equipment and surrounding area should be cleaned prior to any major maintenance work.

• All spills should be cleaned up promptly, to reduce the spread of enzyme and limit mechanical damage to the encapsulated material.

• Adequate ventilation should be provided during clean up of spills.

• Do not sweep, brush or use air blowing or high pressure water jets to clean up spills.

• Clean all floors and equipment by washing, gentle shovelling, vacuuming or mopping.

• To avoid the generation of dust, enzyme granulate and enzymatic detergent spills should be vacuumed or gently shovelled up.

• To avoid the generation of aerosols, liquid enzyme and detergent spills should be cleaned up using low pressure water.

• Big bags should be returned to the suppliers of the enzymes where possible or disposed of carefully, such as by a licensed operator or contractor.

• Schutz containers should be cleaned with low pressure hot water and reused if possible.

• All enzyme-containing material should be denatured by using heat or hot water (greater than 80ûC) before disposal.

• Plant equipment, including ventilation equipment, should be regularly checked and maintained.

• Workers involved in the manufacture of the proteinase-containing detergents should receive induction and training with respect to the safe handling of enzymes and products containing enzymes.

• Operators of the enzyme feed room, maintenance and reclaim workers should receive specialised training, such as for the wearing and use of respirators.

Personal Protective Equipment

Workers who may come into direct contact with proteinases include:

• workers undertaking normal operations in the enzyme feed rooms, such as replacing big bags or connecting pipes to Schutz containers;

• workers cleaning and maintaining equipment, including ventilation equipment, which has contained proteinases; and

• workers who clean up enzyme spills or clean up major spills of enzymatic detergents.

These workers should:

• wear suitable personal protective equipment, selected and used in compliance with relevant Australian Standards (published by Standards Australia, Sydney), including:

• protective clothing, such as overalls, in accordance with Australian Standard, AS 3765.1 - Clothing for Protection Against Hazardous Chemicals;

• impervious gloves, such as PVC or nitrile gloves, in accordance with Australian Standard, AS 2161 Industrial Safety Gloves and Mittens;

• goggles or safety glasses complying with Australian Standard, AS 1337 - Eye Protection for Industrial Applications, and chosen and used in accordance with Australian Standard, AS 1336 - Recommended Practices for Eye Protection in the Industrial Environment; and

• particulate respirator, Class P1 filter, which complies with Australian Standard, AS 1716 - Respiratory Protective Devices and should be used in accordance with Australian Standard, AS 1715 - Selection, Use and Maintenance of Respiratory Protective Devices.

• observe good personal hygiene practices at work, such as washing after any contact and wearing clean overalls.

Air Monitoring

Atmospheric enzyme and total dust levels should be monitored routinely. Atmospheric monitoring provides a measure of worker exposure, identifies areas where high levels are found and provides a basis for measuring the effectiveness of control improvements.

Sampling time should be the minimum time practicable to indicate peak levels of airborne enzymes.

Air samplers should be located in the enzyme feed room, the enzyme dosing area, filling area and the reclaim room. Records of enzyme and dust levels should be kept and made accessible to employees.

Consideration should be given to developing monitoring methods which allow for the measurement to peak enzyme levels in air.