(CNN) -- Officials in Michigan Thursday urged residents living near the Kalamazoo River oil spill to evacuate the area because of health concerns.
Between 30 and 50 homes are thought to be affected by the request, which was made by the Calhoun County Public Health Department.
The Environmental Protection Agency indicated Thursday the spill is largely contained.
Oil leaked Monday from a 30-inch pipeline, owned by Enbridge Energy Partners -- moving from Talmadge Creek into the Kalamazoo River, which flows from near the city of Battle Creek into Lake Michigan. The pipeline normally carries 190,000 barrels of oil per day from Griffith, Indiana, to Sarnia, Ontario.
The leak was stopped Tuesday, but not before an estimated 19,500 barrels of oil slipped out. The cause of the spill is under investigation.
"The Health Department is recommending evacuation due to the higher-than-acceptable levels of benzene found in air quality tests and the adverse long-term affect associated with exposure," officials said in a statement.
Benzene can cause drowsiness, dizziness, rapid or irregular heartbeat, headaches, tremors, confusion, or unconsciousness, the department said.
Health officials have advised residents to stay away from oil fumes and to avoid the spill site.
The spill covers 25 miles and resources will be put in full force to prevent it from contaminating Morrow Lake and Lake Michigan, Environmental Protection Agency's Ralph Dollhopf said Thursday.
"We don't anticipate (the spill) getting beyond the containment it already has," Dollhopf.
Enbridge said that 2,400 barrels of oil have been recovered and pumped into large tanks by noon Thursday. An additional 10,000 barrels of oil have been isolated into a holding area and will be pumped into holding tanks, the company said.
Enbridge and the EPA doubled their resources in their bid to contain and clean up the spill and crews were busy along the river Thursday.
Mark Durno, the EPA's deputy incident commander for the site, said that the oil hadn't reached the popular Morrow Lake, between Battle Creek and the city of Kalamazoo, and that holding the oil back from the lake will be "the last line of defense."
Tom Sands, a Michigan state police captain overseeing Michigan's emergency response, said he saw an oil sheen on the lake. He also said containment efforts were falling short. He said he perused the area the day before and said more collections sites were needed.
"This is a serious situation and we need more resources to that area," Sands said.
The action came a day after Gov. Jennifer Granholm demanded a large response to the spill, which was estimated at 19,500 barrels of oil.
Enbridge Energy Partners stopped the leak from its pipeline and is committed to cleaning up the oil, its CEO said Wednesday.
"Our intent is to return your community and the waterways to its original state," Patrick Daniel said at a news conference in Battle Creek, Michigan. "We've made significant progress since yesterday. We still have a lot of work to do."
The company set up a website (www.response.enbridgeus.com) and a toll-free number (800-306-6837) for residents and volunteers.
A Calhoun County Health Department water advisory was issued for anyone with an underground well within 200 feet of the river's banks as a precaution until the water quality can be evaluated, Health Officer Jim Rutherford said at a news conference Thursday. Bottled water will be available for affected residents, which is approximately 100 households.