| SC 13G/A | 2015-01-23 | BlackRock Inc. | US ECOLOGY, INC. | 1,830,641 | 8.5% | EDGAR |
| SC 13G/A | 2014-06-10 | PRICE T ROWE ASSOCIATES INC /MD/ | US ECOLOGY, INC. | 2,251,497 | 10.4% | EDGAR |
| SC 13G/A | 2014-02-14 | KILLEN GROUP INC | US ECOLOGY, INC. | 980,446 | 4.6% | EDGAR |
| SC 13G/A | 2014-02-13 | PRICE T ROWE ASSOCIATES INC /MD/ | US ECOLOGY, INC. | 1,283,940 | 6.0% | EDGAR |
| SC 13G/A | 2014-02-12 | VANGUARD GROUP INC | US ECOLOGY, INC. | 633,272 | 3.0% | EDGAR |
| SC 13G/A | 2014-01-31 | BlackRock Inc. | US ECOLOGY, INC. | 1,245,601 | 5.9% | EDGAR |
| SC 13G/A | 2013-04-23 | HEIL EDWARD F/IL/ | US ECOLOGY, INC. | 825,802 | 4.5% | EDGAR |
| SC 13G/A | 2013-02-20 | KILLEN GROUP INC | US ECOLOGY, INC. | 1,594,688 | 8.7% | EDGAR |
| SC 13G/A | 2013-02-11 | VANGUARD GROUP INC | US ECOLOGY, INC. | 1,029,493 | 5.6% | EDGAR |
| SC 13G/A | 2013-02-08 | PRICE T ROWE ASSOCIATES INC /MD/ | US ECOLOGY, INC. | 1,206,010 | 6.5% | EDGAR |
| SC 13G/A | 2013-02-05 | BlackRock Inc. | US ECOLOGY, INC. | 1,098,682 | 6.0% | EDGAR |
| SC 13G/A | 2012-02-09 | PRICE T ROWE ASSOCIATES INC /MD/ | US ECOLOGY, INC. | 1,182,870 | 6.4% | EDGAR |
| SC 13G/A | 2012-02-09 | VANGUARD GROUP INC | US ECOLOGY, INC. | 938,809 | 5.1% | EDGAR |
| SC 13G/A | 2012-02-08 | BlackRock Inc. | US ECOLOGY, INC. | 1,051,266 | 5.7% | EDGAR |
| SC 13G/A | 2012-02-07 | HEIL EDWARD F/IL/ | US ECOLOGY, INC. | 1,226,866 | 6.7% | EDGAR |
| SC 13G | 2012-02-03 | HEIL EDWARD F/IL/ | US ECOLOGY, INC. | 1,182,700 | 6.5% | EDGAR |
| SC 13G/A | 2011-02-10 | PRICE T ROWE ASSOCIATES INC /MD/ | US ECOLOGY, INC. | 1,156,250 | 6.3% | EDGAR |
| SC 13G | 2011-02-10 | VANGUARD GROUP INC | US ECOLOGY, INC. | 916,275 | 5.0% | EDGAR |
| SC 13G | 2011-02-09 | BlackRock Inc. | US ECOLOGY, INC. | 977,216 | 5.3% | EDGAR |
| SC 13D/A | 2010-11-04 | HEIL EDWARD F/IL/ | US ECOLOGY, INC. | 76,866 | 0.1% | EDGAR |