Methods

Identification of cleaning product and ingredients of concern
Evaluation of product lines and identification of chemical ingredients
Information on major products lines and brand names of cleaning product was obtained by interviewing environmental services representatives of six hospitals in Eastern Massachusetts. Hospitals selected represent a full range of in-patient and outpatient services and were located in several cities. They included three large sized urban teaching hospitals, one medium sized urban hospital, and two medium sized suburban hospitals.

We conducted interviews of cleaning workers and performed and observational surveys to identify the products used daily and the associated cleaning tasks. Material Safety Data Sheets (MSDSs) of the products were collected on site or obtained by the manufacturers’ web sites. MSDSs of both the concentrated form and ready to use (RTU) form of all products were reviewed. The concentrated forms were evaluated even when only the RTU form was actually used in order to identify ingredients of the mixture with concentrations of less than 1% by weight, that are not reported from the MSDSs of RTU products. Information collected from MSDSs included hazardous ingredients as listed, their concentration in the mixture and chemical abstract services (CAS) numbers.

Determination of ingredients of concern in cleaning product
A list of chemical ingredients identified from MSDSs was created. Because cleaners were mixtures of many ingredients, a set of criteria was developed to prioritize ingredients for further exposure assessment evaluation. An ingredient was considered to be of concern if: 1) it occurred frequently in multiple cleaning product, 2) it was likely to cause respiratory and skin irritation and sensitization, 3) it occurred at higher concentrations compared to other ingredients in the product, or 4) had higher potential to become airborne compared to other mixture ingredients. First, a frequency analysis allowed identification of chemical ingredients that occurred at least three times in different products. Among them, all potential sensitizers were prioritized despite their concentration percentage in the product. Irritant ingredients were further prioritized based on their exposure potential during product application in the workplace (using criteria 3 and 4).

Potential health effects of identified ingredients, together with their physical-chemical properties were researched through literature review and online search of Toxnet’s Hazardous Substances Data Bank (HSDB) and ChemIDplus [19], the ACGIH 2008 TLVs and BEIs booklet [20], and the NIOSH pocket guide to chemical hazards [21]. Applying the previously defined criteria, we prioritized ingredients among the large number of ingredient comprising cleaning mixtures. These ingredients were in the center of our further exposure assessment evaluation.

Assessment of the potential for inhalation and dermal exposures
Identification of common cleaning tasks
Industrial hygiene worksite observation, interviews with workers, and videotaping of cleaning tasks were performed in three hospitals. Observations and interviews were performed for several hours while the workers were performing the tasks. Process flow charts were developed to identify cleaning tasks, which were used as a unit of exposure analysis. A “task” was defined as a cleaning activity that required application of one single product. Examples of common cleaning tasks performed include floor cleaning, mirror cleaning, toilet bowl cleaning, counter cleaning and floor finishing tasks.

Qualitative assessment of inhalation exposures
Potential inhalation exposures to ingredients of concern were assessed for each of the cleaning tasks identified. That was done qualitatively by taking into account both product formulations and task performance. Product formulation impacts directly the exposure intensity, depending on the volatility and concentration of ingredient in the product. Data on ingredients’ volatility and concentrations were collected through literature searches and MSDSs review, respectively. Volatile organic compounds (VOC) were defined as compounds with boiling point between 0 – 400°C [1]. Boiling points were used relatively to assess the potential for inhalation exposures from different products; for example products that contain volatile ingredients with lower boiling points were considered to generate higher VOC exposures relative to others. Data on product application procedures (such as spraying vs. mopping), task duration and frequency were collected through workplace observations, videotaping and interviews of workers. Qualitative categorization of exposure intensity into low, medium and high, in combinations with task duration and frequency allowed classification of cleaning tasks in three potential inhalation exposure categories: low, medium, and high.

Semi-qualitative assessment of dermal exposures
The Dermal Exposure Assessment Method (DREAM), a validated semi-quantitative method for assessing dermal exposures, was applied to assess the potential for dermal exposure from common cleaning tasks [22–24]. The DREAM method is based on the conceptual model developed by Schneider that considers three major mechanisms by which the contaminant can contact the skin: emission, deposition and transfer[25]. Emission is the transport of substances from primary sources to the skin in the form of vapors or particles that can happen through splashing and spilling, for example. Deposition is the transport from air to the skin and it is dependent on the deposition velocity, concentration of the chemical in air and area of the skin contact. Transfer is the transport of substances by direct contact with skin for example from contaminated working tools [22].