Investors in cleaning products supplier Ecolab ( ECL ) have enjoyed steady dividend growth and capital appreciation over many years. But Zacks Equity Research said Dec. 21 that it's concerned about currency fluctuations and "aggressive competition" from rivals Clorox ( CLX ) and Church & Dwight ( CHD ). "Sluggish European markets and raw material price inflation also remain head winds," said Zacks, which has a neutral rating on Ecolab's shares.