rules or orders.” Tex. Health & Safety Code Ann. § 382.113(a). The legislature imposed only the two restrictions previously mentioned: an ordinance must be consistent with the Act and the commission’s rules and orders and may not make unlawful a condition or act approved or authorized under the Act or the commission’s rules or orders. Id. § 382.113(b). If the ordinance violates one of these restrictions, however, then its preemption is implied with unmistakable clarity. We therefore turn next to the first of these restrictions and address the question of whether the Act and the ordinance are consistent. 3. The Clean Air Act and the tent with state legislation, we begin by comparing the purpose of each. See City of Weslaco v. Melton, 158 Tex. 61, 63-64, 308 S.W.2d 18, 19-20 (1958) (<HOLDING>); see also City of Brookside Vill. v. Comeau,
recognizing the two different types of conspiracies under the federal statute holding state and federal actions not parallel for colorado river purposes because the remedies were different  one was equitable and the other compensatory  and the sources of law came from different states holding that an implied warranty of merchantability does not create a labeling requirement different from or in addition to those mandated by fifra because the implied warranty of merchantability arises from the sale itself not from a state labeling regulation citation omitted holding that completing sixth grade and a limited ability to read were not inconsistent with a valid iq score of 68 holding that an ordinance banning the sale of grade a raw milk was not inconsistent with a state statute for grading and labeling milk because the two provisions served different purposes