But advocates and residents living near oil and gas wells believe otherwise. In the last two years, the Texas commission has received more than 400 complaints related to air quality that residents believed resulted from drilling in the Barnett and Eagle Ford shales.

Many describe headaches, dizziness, itchy eyes and nosebleeds; others claim more serious effects, like lung disease. The symptoms are consistent with Environmental Protection Agency descriptions of possible exposure to emissions from oil and gas drilling.

But despite all those complaints, and thousands of oil and gas leases in the shale regions, the state commission has levied 35 fines in last two fiscal years.

The commission made documentation available for only two of the fines. In 2013, the drilling company Wiley Lease was ordered to pay $6,250 for releasing air contaminants, without the proper permit, from a wastewater disposal site in South Texas’ Atascosa County. The company was told to get the permit retroactively, after which the same emissions would be allowed.

And last summer, Swift Energy Operating was fined $14,280 for odors around a drilling site that, according to agency investigators, “may be injurious to or adversely affect human health or welfare.” In documents, the agency said its staff “experienced irritation of the eyes and a burning sensation in the throat” during each of four visits to Swift’s La Salle County operations in South Texas in 2013.

Swift Energy paid $11,400 of the fine, the agency said, “upon timely and satisfactory compliance,” which involved mostly repairing equipment leaks.

Such low fines do not carry enough weight to compel companies to regularly follow the rules, said Hugh Fitzsimons, a rancher near the Mexican border who has seen an explosion of drilling activity on his 11,000-acre property. (Mr. Fitzsimons is a major donor to The Texas Tribune.)