Oil Spill Cleanup Workers Research Articles

Fine particulate matter from burning oil and gas and neurological symptoms among oil spill cleanup workers

Fine particulate matter from burning oil and gas and neurological symptoms among oil spill cleanup workers

Latent Trajectories of Haematological, Hepatic, and Renal Profiles after Oil Spill Exposure: A Longitudinal Analysis.

Exposure to polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) in crude oil has carcinogenic effects on various organ systems. This longitudinal cohort study examined the effects of oil spill exposure on the haematological, hepatic, and renal profiles of Rayong oil spill clean-up workers. The sample included 869 clean-up workers from the Rayong oil spill. Latent class mixture models were used to investigate and classify the longitudinal trajectories and trends of the haematological, hepatic, and renal indices. Subgroup analysis was used to evaluate the association between the urinary metabolites of PAHs and VOCs and haematological, hepatic, and renal parameters. Most clean-up workers (97.6%) had increasing levels of white blood cells (WBCs) (0.03 × 103 cells/µL), 94.90% of the workers had a significantly increasing trend of blood urea nitrogen (0.31 mg/dL per year), and 87.20% had a significantly increasing trend of serum creatinine (0.01 mg/dL per year). A high-decreasing trend of WBCs was seen in 2.42% (-0.73 × 103 per year). Post-exposure changes in haematological, renal, and hepatic profiles are present in workers exposed to the Rayong oil spill. This indicates possible long-term health complications and worsening renal function after exposure to PAHs and VOCs in crude oil.

Associations between airborne crude oil chemicals and symptom-based asthma.

The 2010 Deepwater Horizon (DWH) oil spill response and cleanup (OSRC) workers were exposed to airborne total hydrocarbons (THC), benzene, toluene, ethylbenzene, o-, m-, and p-xylenes and n-hexane (BTEX-H) from crude oil and PM2.5 from burning/flaring oil and natural gas. Little is known about asthma risk among oil spill cleanup workers. We assessed the relationship between asthma and several oil spill-related exposures including job classes, THC, individual BTEX-H chemicals, the BTEX-H mixture, and PM2.5 using data from the Gulf Long-Term Follow-up (GuLF) Study, a prospective cohort of 24,937 cleanup workers and 7,671 nonworkers following the DWH disaster. Our analysis largely focused on the 19,018 workers without asthma before the spill who had complete exposure, outcome, and covariate information. We defined incident asthma 1-3years following exposure using both self-reported wheeze and self-reported physician diagnosis of asthma. THC and BTEX-H were assigned to participants based on measurement data and work histories, while PM2.5 used modeled estimates. We used modified Poisson regression to estimate risk ratios (RR) and 95% confidence intervals (CIs) for associations between spill-related exposures and asthma and a quantile-based g-computation approach to explore the joint effect of the BTEX-H mixture on asthma risk. OSRC workers had greater asthma risk than nonworkers (RR: 1.60, 95% CI: 1.38, 1.85). Higher estimated THC exposure levels were associated with increased risk in an exposure-dependent manner (linear trend test p<0.0001). Asthma risk also increased with increasing exposure to individual BTEX-H chemicals and the chemical mixture: A simultaneous quartile increase in the BTEX-H mixture was associated with an increased asthma risk of 1.45 (95% CI: 1.35,1.55). With fewer cases, associations were less apparent for physician-diagnosed asthma alone. THC and BTEX-H were associated with increased asthma risk defined using wheeze symptoms as well as a physician diagnosis.

Biological effects of inhaled crude oil vapor V. Altered biogenic amine neurotransmitters and neural protein expression

Workers in the oil and gas industry are at risk for exposure to a number of physical and chemical hazards at the workplace. Chemical hazard risks include inhalation of crude oil or its volatile components. While several studies have investigated the neurotoxic effects of volatile hydrocarbons, in general, there is a paucity of studies assessing the neurotoxicity of crude oil vapor (COV). Consequent to the 2010 Deepwater Horizon (DWH) oil spill, there is growing concern about the short- and long-term health effects of exposure to COV. NIOSH surveys suggested that the DWH oil spill cleanup workers experienced neurological symptoms, including depression and mood disorders, but the health effects apart from oil dispersants were difficult to discern. To investigate the potential neurological risks of COV, male Sprague-Dawley rats were exposed by whole-body inhalation to COV (300 ppm; Macondo surrogate crude oil) following an acute (6 h/d × 1 d) or sub-chronic (6 h/d × 4 d/wk. × 4 wks) exposure regimen. At 1, 28 or 90 d post-exposure, norepinephrine (NE), epinephrine (EPI), dopamine (DA) and serotonin (5-HT) were evaluated as neurotransmitter imbalances are associated with psychosocial-, motor- and cognitive- disorders. Sub-chronic COV exposure caused significant reductions in NE, EPI and DA in the dopaminergic brain regions, striatum (STR) and midbrain (MB), and a large increase in 5-HT in the STR. Further, sub-chronic exposure to COV caused upregulation of synaptic and Parkinson's disease-related proteins in the STR and MB. Whether such effects will lead to neurodegenerative outcomes remain to be investigated.

Haematological, renal, and hepatic function changes among Rayong oil spill clean-up workers: a longitudinal study.

The Rayong oil spill incident of 2013 leaked over 50,000 barrels of crude oil into the Gulf of Thailand. This study assessed trends and changes in the haematological, renal, and hepatic indices among the Rayong oil spill clean-up workers 5years after the spill. Haematological, renal, and hepatic indices measured for 570 oil spill clean-up workers at baseline and annually during 5-year follow-ups were analysed. Haemoglobin (Hb), haematocrit (Hct), white blood cell (WBC) count, red blood cell (RBC) count, and platelet count for haematological function, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) for hepatic function, and creatinine (Cr) and blood urea nitrogen (BUN) for renal function were assessed. The longitudinal measures of haematological, renal and hepatic indices were analysed using analysis of variance for repeated measures. The generalised estimating equations (GEE) were used to assess trends of these indices and associated factors, including exposure level. Increasing trends were observed per year for WBC (0.52 ± 0.03 × 103 cells/μL), Cr (0.01 ± 0.00mg/dL), platelet (0.31 × 103 μL per year), and BUN (0.24 ± 0.03mg/dL). Decreasing trends of aspartate aminotransferase (AST) were observed (1.54 ± 0.21IU/L per year). Clean-up workers with high exposure to the oil spill had a significantly higher average of WBC and lower average of BUN than low-exposure and unknown-exposure workers. Gender and age were significantly associated with creatinine changes. Results of this study show the differences between baseline and follow-up haematological, renal, and hepatic indices and trends of these indices. The long-term changes in the indices in this study show worsening renal functions after oil spill and possibility of cardiovascular effects. These findings contribute to expanding knowledge on the long-term health effects of oil spills.

EXPOSURE ASSESSMENT OF RAYONG OIL SPILL CLEANUP WORKERS.

In July of 2013, a pipeline connecting an offshore oil platform to a tanker caused crude oil to spill into the Sea of Rayong off the coast of Thailand. The resulting oil slick, estimated to be between 50 and 190 cubic meters (336-1,200 barrels), washed ashore one day later on the island of Samet. We conducted a study to quantify internal dose of polycyclic aromatic hydrocarbons (PAHs) and benzene in 1,262 oil spill cleanup workers, and to examine factors related to their dose. Frozen stored urine samples (n=1343) collected from the workers during the one month cleanup period were used to measure the concentration of 1-hydroxypyrene-glucuronide (1-OHPG), cotinine and creatinine. Data from questionnaires and urinary trans,trans-muconic acid (t,t-MA), a benzene metabolite, measured previously as part of a worker health surveillance plan, were linked with the laboratory data. The internal dose of urinary 1-OHPG was highest in individuals who worked during the first 3 days of cleanup work (median: 0.97 pmol/ml) and was 66.7% lower (median: 0.32 pmol/ml) among individuals who worked in the final week of the study (days 21-28). After adjusting for age, cotinineand creatinine by regression analysis, the decline in urinary 1-OHPG concentration with days of cleanup remained significant (P-trend <0.001). A decreasing trend by days of cleanup was also observed for detectable urinary t,t-MA percentage (P-trend <0.001). Rayong oil spill cleanup workers exhibited evidence of elevated levels of PAH and benzene exposure during the early weeks of cleanup, compared to near background levels 4 weeks after cleanup began. Long-term health monitoring of oil spill cleanup workers is advised.

The Development of Long-Term Adverse Health Effects in Oil Spill Cleanup Workers of the Deepwater Horizon Offshore Drilling Rig Disaster.

The purpose of this study was to assess the long-term adverse health effects of the 2010 Deepwater Horizon Gulf oil spill exposure in workers who participated in its cleanup work. Medical charts of both the oil spill exposed and unexposed subjects were reviewed. The changes in the white blood cells, platelets, hemoglobin, hematocrit, blood urea nitrogen, creatinine, alkaline phosphatase (ALP), aspartate amino transferase (AST), alanine amino transferase (ALT) levels, as well as their pulmonary and cardiac functions were evaluated. Medical records from 88 subjects (oil spill cleanup workers, n = 44 and unexposed, n = 44) were reviewed during initial and 7 years follow up visits after the disaster occurred. Compared with the unexposed subjects, oil spill exposed subjects had significantly reduced platelet counts (×103/µL) at their initial (254.1 ± 46.7 versus 289.7 ± 63.7, P = 0.000) and follow-up (242.9 ± 55.6 versus 278.4 ± 67.6, P = 0.000) visits compared with the unexposed subjects (254.6 ± 51.9 versus 289.7 ± 63.7, P = 0.008). The hemoglobin and hematocrit levels were increased significantly both at their initial and follow-up visits in the oil spill exposed subjects compared to the unexposed subjects. Similarly, the oil spill exposed subjects had significantly increased ALP, AST, and ALT levels at their initial and follow-up visits compared with those of the unexposed subjects. Illness symptoms that were reported during their initial visit still persisted at their 7-year follow-up visit. Notably, at their 7-year follow-up visit, most of the oil spill exposed subjects had also developed chronic rhinosinusitis and reactive airway dysfunction syndrome as new symptoms that were not reported during their initial visit. Additionally, more abnormalities in pulmonary and cardiac functions were also seen in the oil spill exposed subjects. This long-term follow-up study demonstrates that those people involved in the oil spill cleanup operations experiences persistent alterations or worsening of their hematological, hepatic, pulmonary, and cardiac functions. In addition, these subjects experienced prolonged or worsening illness symptoms even 7 years after their exposure to the oil spill.

Mental health indicators associated with oil spill response and clean-up: cross-sectional analysis of the GuLF STUDY cohort

Adverse mental health effects have been reported following oil spills but few studies have identified specific responsible attributes of the clean-up experience. We aimed to analyse the effects of the 2010 Deepwater Horizon (Gulf of Mexico) disaster on the mental health of individuals involved in oil spill response and clean-up. We used data from the Gulf Long-term Follow-up Study, a cohort of workers and volunteers involved in oil spill clean-up after the Deepwater Horizon disaster. We included 8968 workers (hired after completing training for oil spill response and clean-up) and 2225 non-workers (completed training but were not hired) who completed a Patient Health Questionnaire-8 and four-item Primary Care PTSD Screen to assess for probable depression and post-traumatic stress disorder (PTSD) indicators. Participants were recruited between March 28, 2011, and March 29, 2013. The mental health indicators were assessed at home visits done between May 12, 2011, and May 15, 2013. We used regression models to analyse the effect of potentially stressful job experiences, job type, and total hydrocarbon exposure on mental health indicators. Oil spill response and clean-up work was associated with increased prevalence of depression (prevalence ratio [PR] 1·22, 95% CI 1·08-1·37) and PTSD (PR 1·35, 95% CI 1·07-1·71). Among workers, individuals who reported smelling oil, dispersants, or cleaning chemicals had an elevated prevalence of depression (1·56, 1·37-1·78) and PTSD (2·25, 1·71-2·96). Stopping work because of the heat was also associated with depression (1·37, 1·23-1·53) and PTSD (1·41, 1·15-1·74), as was working as a commercial fisherman before the spill (1·38, 1·21-1·57; and 2·01, 1·58-2·55, respectively). An increase in exposure to total hydrocarbons appeared to be associated with depression and PTSD, but after taking into account oil spill job experiences, only the association between the highest amount of total hydrocarbons and PTSD remained (1·75, 1·11-2·76). Oil spill clean-up workers with high amounts of total hydrocarbon exposure or potentially stressful job experiences had an increased prevalence of depression and PTSD. These findings provide evidence that response and clean-up work is associated with adverse psychological effects and suggest the need for mental health services both before and after the event. National Institutes of Health (NIH) Common Fund and the Intramural Research Program of the NIH, National Institute of Environmental Health Sciences.

Development of an In Vitro Exposure System for Live Visualization of the Health Impacts of Oily Marine Aerosol on the Human Respiratory System

Aerosolization of oily water droplets has recently been recognized as a potential respiratory health threat to oil spill cleanup workers, communities near spills, and marine mammals in oil-polluted waters. These sub-micron to millimeter scale droplets may be aerosolized by bursting bubbles, breaking waves, and splashing raindrops. Furthermore, dispersant applied to oil slicks also may become aerosolized as oil-water-dispersant emulsion droplets and subsequently inhaled, with unknown health consequences. With the goal of investigating the effects of inhaled oily marine aerosol on human lung health, we present the design of a novel in vitro bioreactor which mimics the conditions and exposures that human lungs might experience in the field. The bioreactor provides the ability to expose human lung cell cultures to laboratory-produced, well-characterized and chemically analyzed oily marine aerosols. A major advance over similar systems currently used to study the effects of smoking is the incorporation of optical access to allow visualization of the cells throughout exposure. In the bioreactor, differentiated, primary human bronchial epithelial cell cultures reside on membranes at the air-liquid interface between the flow-through test atmosphere and a temperature-controlled bath of culture media, thereby simulating the human lung. Oily marine aerosol is produced by a 1-Jet Collison Nebulizer (Mesa Labs Inc.) to match realistic concentrations produced and measured in a wave tank and is sampled via scanning mobility particle sizer (TSI Inc) to characterize its size distribution. The aerosol-laden air is humidified and injected at a controlled flow rate of ~1 ml/s into a module containing the cell culture, allowing particles to deposit on the cells. The module has sealed glass windows to allow optical access. An optical setup incorporating a 20× long-distance objective, 1× tube lens, and camera is used to visualize the cells over time. Preliminary testing involves determining the effectiveness of deposition of oily marine aerosol droplets at various concentrations onto the cell culture surface. Phase contrast microscopy is used to examine contact between cells as a determinant of monolayer integrity. Immunofluorescence of live cells is used with FITC- or mCherry-labelled cytoskeletal and cell-cell adhesion proteins, such as actin and E-cadherin, to determine underlying mechanisms disrupting the monolayer. A system such as this allowing for live visualization of cells during the exposure currently does not exist and will provide significant understanding of how changes within the epithelium may disrupt tissue integrity in response to inhalation of oily marine aerosol.

Respiratory Symptoms in Oil Spill Clean-Up Workers Participating in the Gulf STUDY

Respiratory Symptoms in Oil Spill Clean-Up Workers Participating in the Gulf STUDYAbstract Number:2278 Dale Sandler*, Lawrence Engel, John McGrath, Julianne Payne, Kathryn Rose, Christine Ekenga, Matthew Curry, Aubrey Miller, Aaron Blair, Linda Birnbaum, and Richard Kwok Dale Sandler* National Institute of Environmental Health Sciences, NIH, United States, E-mail Address: [email protected] Search for more papers by this author , Lawrence Engel University of North Carolina, United States, E-mail Address: [email protected] Search for more papers by this author , John McGrath Social and Scientific Systems, Inc., United States, E-mail Address: [email protected] Search for more papers by this author , Julianne Payne Social and Scientific Systems, Inc., United States, E-mail Address: [email protected] Search for more papers by this author , Kathryn Rose Social and Scientific Systems, Inc, United States Search for more papers by this author , Christine Ekenga National Institute of Environmental Health Sciences, United States, E-mail Address: [email protected] Search for more papers by this author , Matthew Curry Social and Scientific Systems, Inc, United States, E-mail Address: [email protected] Search for more papers by this author , Aubrey Miller National Instsitute of Environmental Health Sciences, United States, E-mail Address: [email protected] Search for more papers by this author , Aaron Blair National Cancer Institute, United States, E-mail Address: [email protected] Search for more papers by this author , Linda Birnbaum National Institute of Environmental Health Sciences, United States, E-mail Address: [email protected] Search for more papers by this author , and Richard Kwok National Instistute of Environmental Health Sciences, United States, E-mail Address: [email protected] Search for more papers by this author AbstractBackground: Little is known about long-term health effects of oil spills, but previous studies found respiratory effects. The 2010 Deepwater Horizon explosion in the Gulf of Mexico led to the largest ever marine oil spill. We assessed respiratory symptoms in the GuLF STUDY, a prospective study of 32,736 adults who participated in oil spill clean-up or were eligible but not hired.Methods: Demographic, exposure, and health information was collected in telephone interviews. Participants were asked how often they had cough, wheezing, tightness in their chest, or shortness of breath during the oil spill and in the 30 days prior to interview (1-3 years later). Jobs were rated by study industrial hygienists as high, medium, or low oil exposure or unexposed. We calculated adjusted prevalence ratios (PR) and 95% confidence intervals (CI) for associations between oil spill work and frequent symptoms (‘most’ or ‘all of the time’) using log-binomial regression. Covariates included demographic, socioeconomic, and lifestyle factors, residence in a Gulf county, perceived stress, and obesity.Results: The prevalence of symptoms at enrollment was 6% for tightness in the chest, 9% for shortness of breath, 10% for wheeze, and 16% for cough. Working on the oil spill was associated with the four respiratory symptoms at both time periods. Among never smokers without prior lung disease, the adjusted PR was 1.39 (95% CI 1.15, 1.68) for wheeze during the spill and 1.87 (95% CI 1.53, 2.29) for wheeze at the time of interview. The prevalence of wheeze at interview rose with likelihood of oil exposure; PR were 1.03 (0.76, 1.42), 1.44 (1.11, 1.88), and 2.36 (1.92, 2.90) for workers in low, medium and high exposure jobs compared to nonworkers.Conclusions: One to three years after the Deepwater Horizon disaster, oil spill clean-up work was associated with an increased prevalence of respiratory symptoms. Ongoing follow-up will assess persistence of effects.

Evaluation of Pulmonary and Systemic Toxicity of Oil Dispersant (COREXIT EC9500A(®)) Following Acute Repeated Inhalation Exposure.

INTRODUCTIONOil spill cleanup workers come into contact with numerous potentially hazardous chemicals derived from the oil spills, as well as chemicals applied for mitigation of the spill, including oil dispersants. In response to the Deepwater Horizon Macondo well oil spill in the Gulf of Mexico in 2010, a record volume of the oil dispersant, COREXIT EC9500A, was delivered via aerial applications, raising concern regarding potential health effects that may result from pulmonary exposure to the dispersant.METHODSThe current study examined the effects on pulmonary functions, cardiovascular functions, and systemic immune responses in rats to acute repeated inhalation exposure of COREXIT EC9500A at 25 mg/m3, five hours per day, over nine work days, or filtered air (control). At one and seven days following the last exposure, a battery of parameters was measured to evaluate lung function, injury, and inflammation; cardiovascular function; peripheral vascular responses; and systemic immune responses.RESULTSNo significant alterations in airway reactivity were observed at one or seven days after exposure either in baseline values or following methacholine (MCh) inhalation challenge. Although there was a trend for an increase in lung neutrophils and phagocyte oxidant production at one-day post exposure, there were no significant differences in parameters of lung inflammation. In addition, increased blood monocytes and neutrophils, and decreased lymphocyte numbers at one-day post exposure also did not differ significantly from air controls, and no alterations in splenocyte populations, or serum or spleen immunoglobulin M (IgM) to antigen were observed. There were no significant differences in peripheral vascular responsiveness to vasoconstrictor and vasodilator agonists or in blood pressure (BP) responses to these agents; however, the baseline heart rate (HR) and HR responses to isoproterenol (ISO) were significantly elevated at one-day post exposure, with resolution by day 7.CONCLUSIONSIn summary, acute repeated exposure to COREXIT EC9500A did not alter pulmonary function, lung injury/inflammation, systemic immune responses, or vascular tone, but did cause transient chronotropic effects on cardiac function.

Analysis and Modeling of Airborne BTEX Concentrations from the Deepwater Horizon Oil Spill

Concerns have been raised about whether the Deepwater Horizon oil spill cleanup workers experienced adverse health effects from exposure to airborne benzene, toluene, ethylbenzene, and xylene (BTEX) which volatilized from surfaced oil. Thus, we analyzed the nearly 20 000 BTEX measurements of breathing zone air samples of offshore cleanup workers taken during the six months following the incident (made publicly available by British Petroleum). The measurements indicate that 99% of the measurements taken prior to capping the well were 32-, 510-, 360-, and 77-fold lower than the U.S. Occupational Safety and Health Administration's Permissible Exposure Limits (PELs) for BTEX, respectively. BTEX measurements did not decrease appreciably during the three months after the well was capped. Moreover, the magnitudes of these data were similar to measurements from ships not involved in oil slick remediation, suggesting that the BTEX measurements were primarily due to engine exhaust rather than the oil slick. To supplement the data analysis, two modeling approaches were employed to estimate airborne BTEX concentrations under a variety of conditions (e.g., oil slick thickness, wind velocity). The modeling results corroborated that BTEX concentrations from the oil were well below PELs and that the oil was not the primary contributor to the measured BTEX.

OCCUPATIONAL HEALTH: Study to Examine Health Effects in Deepwater Horizon Oil Spill Cleanup Workers

In the wake of the BP Deepwater Horizon disaster in the Gulf of Mexico, the National Institute of Environmental Health Sciences (NIEHS) has launched the largest study ever on the health consequences of oil spill cleanup.1 Led by Dale Sandler, who heads the NIEHS’s intramural Epidemiology Branch, the GuLF STUDY (Gulf Long-term Follow-up study) aims to enroll 55,000 workers and volunteers involved in the BP oil spill response, including 5,000 controls.2 National Institutes of Health director Francis Collins pledged $10 million for the study on 15 June 2010.3 Sandler says the full cohort should be assembled within 18–24 months. “We’ve got funding for five years, but we designed the study so it can go up to twenty years,” she says. “If we want to assess links between oil spill response and rare cancers, we’ll have to go that far.” Nalini Sathiakumar, an environmental and occupational epidemiologist at the University of Alabama at Birmingham School of Public Health, says the GuLF STUDY’s size and prospective design distinguish it from earlier health investigations of oil spill responses. “Previous studies primarily examined short-term health effects and were cross-sectional, meaning they looked at exposure outcomes at just one time point,” she says. “What you really want to do is a longitudinal assessment of exposure–outcome relationships, and that’s what this study does.” According to Sandler, the GuLF STUDY will focus especially on respiratory, neurological, and hematological outcomes linked in the toxicologic literature to oil constituents. And taking a cue from other environmental disasters such as the nuclear incident at Three Mile Island and the World Trade Center attacks, she says, where many people reported mental stress,4,5 the GuLF STUDY will also investigate psychological outcomes in relation to cleanup and living in the Gulf region. Exposure to volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and dispersants will be estimated based partly on environmental monitoring data gathered by agencies and organizations during the response, Sandler says. Those data will be used to construct job-exposure matrices, which will also be informed by self-reported answers to a telephone questionnaire the NIEHS began administering in late March. The questionnaire requests information about where individuals worked during the cleanup, how long they worked, what they did, and whether they used personal protective equipment, in addition to background information about family health history, lifestyle, diet, mental health status, and prior employment history. In addition, investigators will collect samples of blood, hair, toenail, urine, and other biospecimens from about half the participants to search for biomarkers showing some evidence of interaction with or influence on a biological process. DNA adducts, chromosome damage, and altered ability to repair DNA are examples of the sorts of biomarkers being considered. Ideally, the study will allow scientists to link job categories and estimated exposures during the cleanup to a range of frank and subtle health effects over time, Sandler says. The NIEHS will publicize results in periodic summary reports, “and anyone who wants access to the data will be able to submit a request,” Sandler says. “Scientists will have to honor confidentiality—it’s important to respect the privacy of data given to us in confidence.” Bill Farland, senior vice president for research at Colorado State University in Fort Collins and an invited speaker at a June 2010 Institute of Medicine workshop titled “Assessing the Human Health Effects of the Gulf of Mexico Oil Spill,” describes the study as well designed, particularly because it investigates both physiological and mental health outcomes. “What we’re most concerned about are the VOC and PAH exposures,” he says. “This is what people who were exposed to the oil slick itself would have come in contact with.”